Cylindrical battery cell, battery and electric device

Abstract

Provided in the embodiments of the present application are a cylindrical battery cell, a battery and an electric device. The cylindrical battery cell comprises a casing and an electrode assembly. The cylindrical battery cell has a diameter greater than or equal to 40 mm. At least part of the electrode assembly is accommodated in the casing. The electrode assembly comprises a positive electrode sheet, a negative electrode sheet and a separator, wherein the positive electrode sheet, the negative electrode sheet and the separator are wound, the separator keeping the positive electrode sheet and the negative electrode sheet separated. A negative electrode active material of the negative electrode sheet comprises at least one of silicon and carbon. At least one of the positive electrode sheet, the negative electrode sheet and the separator comprises a base portion and a plurality of support portions arranged on the base portion. The base portion has two first surfaces arranged opposite each other along its own thickness. The plurality of support portions protrude from at least one first surface to form a gap between the positive electrode sheet and the negative electrode sheet.

Description

Cylindrical battery cell, battery and electric device TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, and more particularly, to a cylindrical battery cell, a battery and an electric device. BACKGROUND

[0002] Battery cells, particularly cylindrical battery cells, are widely used in electronic devices, such as mobile phones, notebook computers, electric cars, electric cars, electric planes, electric ships, electric toy cars, electric toy ships, electric toy planes, electric tools, and the like.

[0003] With the gradual increase of the requirement for energy density, the diameter of the cylindrical battery cell gradually increases. However, with the gradual increase of the diameter of the cylindrical battery cell, the expansion force of the cylindrical battery cell in the cycle process is also greater, and the expansion force will affect the cycle performance of the cylindrical battery cell. How to improve the cycle performance of the large-diameter cylindrical battery cell is an important research direction in the technical field of batteries.

[0004] SUMMARY

[0005] The present application provides a cylindrical battery cell, a battery and an electric device, which can improve reliability.

[0006] In a first aspect, the embodiments of the present application provide a cylindrical battery cell with a diameter of greater than or equal to 40 mm, comprising a shell and an electrode assembly. At least part of the electrode assembly is accommodated in the shell. The electrode assembly comprises a positive electrode sheet, a negative electrode sheet and a separator, the positive electrode sheet, the negative electrode sheet and the separator are wound and arranged, and the separator separates the positive electrode sheet and the negative electrode sheet. The negative electrode active material of the negative electrode sheet comprises at least one of a silicon-based material and a carbon-based material. At least one of the positive electrode sheet, the negative electrode sheet and the separator comprises a base and a plurality of support portions arranged on the base. The base has two first surfaces oppositely arranged along the thickness direction of itself. The plurality of support portions are protruding on at least one first surface to form a gap between the positive electrode sheet and the negative electrode sheet.

[0007] The plurality of support portions protrude and can support at least one of the positive electrode sheet and the negative electrode sheet to form a gap between the positive electrode sheet and the negative electrode sheet. During the cycle of the cylindrical battery cell, the gap can provide space for the expansion of the negative electrode sheet, thereby reducing the compression of the electrolyte in the internal pores of the positive electrode film layer of the positive electrode sheet and the internal pores of the negative electrode film layer of the negative electrode sheet, reducing the concentration difference of the electrolyte in each region of the electrode sheet, and improving the cycle performance of the cylindrical battery cell with a larger diameter. The gap can reduce the expansion of the electrode assembly, thereby reducing the compression of the shell, reducing the risk of deformation and cracking of the shell, and improving the reliability of the cylindrical battery cell. By providing the gap, the increase in expansion force caused by increasing the diameter of the cylindrical battery cell can be reduced, the diameter of the cylindrical battery cell can be increased, and the capacity of the cylindrical battery cell can be improved.

[0008] In some embodiments, the support portion is configured to be compressible. During the cycle of the cylindrical battery cell, the support portion can be compressed when pressed, thereby providing more expansion space for the negative electrode sheet. The compressible support portion can release stress by compression deformation to reduce the risk of the positive electrode sheet or the negative electrode sheet being crushed by the support portion and improve reliability.

[0009] In some embodiments, the plurality of support portions includes a first support portion and a second support portion, and the height of the first support portion protruding from the first surface is greater than the height of the second support portion protruding from the first surface.

[0010] The first support portion has a greater height, which can support the positive electrode sheet or the negative electrode sheet to form a larger gap, thereby providing more space for the expansion of the negative electrode sheet. The second support portion has a smaller height and occupies less space. As the negative electrode sheet expands, the gap gradually decreases; the second support portion can be pressed after the negative electrode sheet expands to a certain extent, which can reduce the pressure on the negative electrode sheet in the early stage of expansion. When the second support portion is pressed, the second support portion can slow down the expansion of the negative electrode sheet to some extent, reduce the electrolyte squeezed out by the negative electrode sheet, and improve the cycle performance of the cylindrical battery cell.

[0011] In some embodiments, at least one of the positive electrode sheet, the negative electrode sheet, and the separator includes a plurality of organic particles, and the support portion includes the organic particles. The organic particles can support to form a gap. When the cylindrical battery cell experiences thermal runaway, the organic particles can form a gel film structure at high temperature, thereby reducing the diffusion channel of active ions and delaying the time of thermal spread, thereby improving the reliability of the cylindrical battery cell.

[0012] In some embodiments, the plurality of organic particles includes first organic particles and second organic particles, and the first organic particles have a number average particle size greater than the number average particle size of the second organic particles. The first organic particles with a larger number average particle size can support the positive electrode sheet or the negative electrode sheet to form a larger gap, thereby providing more space for the expansion of the negative electrode sheet. The second organic particles with a smaller number average particle size can be compressed after the negative electrode sheet expands to a certain extent, which can reduce the pressure on the negative electrode sheet in the initial stage of expansion. When the second organic particles are compressed, the second organic particles can slow down the expansion of the negative electrode sheet to some extent, reduce the electrolyte squeezed out by the negative electrode sheet, and improve the cycle performance of the cylindrical battery cell.

[0013] In some embodiments, the plurality of support portions includes first support portions and second support portions, and the first support portions have a height protruding from the first surface greater than the height of the second support portions protruding from the first surface. The plurality of organic particles includes first organic particles and second organic particles; the first support portions include the first organic particles, and the second support portions include the second organic particles.

[0014] By providing first organic particles and second organic particles with different number average particle sizes, first support portions and second support portions with different heights can be formed. The first support portions have a larger height, which can support the positive electrode sheet or the negative electrode sheet to form a larger gap, thereby providing more space for the expansion of the negative electrode sheet. The second support portions can be compressed after the negative electrode sheet expands to a certain extent, which can reduce the pressure on the negative electrode sheet in the initial stage of expansion. When the second support portions are compressed, the second support portions can slow down the expansion of the negative electrode sheet to some extent, reduce the electrolyte squeezed out by the negative electrode sheet, and improve the cycle performance of the cylindrical battery cell.

[0015] In some embodiments, the plurality of organic particles includes first organic particles, and the first organic particles include one or more of a homopolymer or copolymer of a fluorine-containing olefin monomer unit, a homopolymer or copolymer of an olefin monomer unit, a homopolymer or copolymer of an unsaturated nitrile monomer unit, a homopolymer or copolymer of an alkylene oxide monomer unit, and a modified compound of each of the above homopolymers or copolymers.

[0016] In some embodiments, the first organic particles include one or more of polytetrafluoroethylene, polychlorotrifluoroethylene, polyfluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyacrylonitrile, polyethylene oxide, a copolymer of different fluorine-containing olefin monomer units, a copolymer of a fluorine-containing olefin monomer unit and an olefin monomer unit, a copolymer of a fluorine-containing olefin monomer unit and an acrylic monomer unit, a copolymer of a fluorine-containing olefin monomer unit and an acrylate monomer unit, and a modified compound of each of the above homopolymers or copolymers.

[0017] In some embodiments, the plurality of organic particles include second organic particles including one or more of a homopolymer or copolymer of an acrylate monomer unit, a homopolymer or copolymer of an acrylic monomer unit, a homopolymer or copolymer of a styrene monomer unit, a polyurethane compound, a rubber compound, and a modified compound of each of the above homopolymers or copolymers.

[0018] In some embodiments, the second organic particles include one or more of a copolymer of an acrylate monomer unit and a styrene monomer unit, a copolymer of an acrylic monomer unit and a styrene monomer unit, a copolymer of an acrylic monomer unit-acrylate monomer unit-styrene monomer unit, a copolymer of a styrene monomer unit and an unsaturated nitrile monomer unit, a copolymer of a styrene monomer unit-olefin monomer unit-unsaturated nitrile monomer unit, and a modified compound of each of the above copolymers.

[0019] In some embodiments, the shell includes a side wall disposed around the electrode assembly, the side wall has a thickness of 0.3 mm to 1.5 mm, and the side wall is made of steel. By providing the gap, the expansion force exerted by the electrode assembly on the side wall is reduced, and thus the side wall made of steel can have a thickness of less than or equal to 1.5 mm, thereby improving the energy density of the cylindrical battery cell.

[0020] In some embodiments, the side wall has a thickness of 0.3 mm to 1.2 mm, optionally 0.3 mm to 0.9 mm, and further optionally 0.3 mm to 0.6 mm.

[0021] In some embodiments, the negative electrode sheet includes a negative electrode current collector and a negative electrode film layer disposed on at least one side of the negative electrode current collector and containing a negative electrode active material. The negative electrode active material includes a silicon-based material, and the silicon element of the silicon-based material has a mass content of 2% to 19% in the negative electrode film layer.

[0022] The introduction of the silicon-based material can improve the capacity of the negative electrode active material and improve the energy density of the cylindrical battery cell. The gap can provide space for the expansion of the negative electrode sheet, thereby reducing the influence of the silicon-based material on the expansion force. The embodiments of the present application limit the mass content of the silicon element of the silicon-based material in the negative electrode film layer to the above range to balance the expansion and capacity of the negative electrode sheet to some extent, and to balance the cycle performance and energy density of the cylindrical battery cell.

[0023] In some embodiments, the silicon element of the silicon-based material has a mass content of 6% to 13% in the negative electrode film layer.

[0024] In some embodiments, the capacity area density of the negative electrode sheet is greater than or equal to 3.2 mAh / cm2 The embodiments of the present application can reduce the influence of increasing the surface density of the negative sheet on the expansion force, thereby improving the capacity of the negative sheet and the energy density of the cylindrical battery cell.

[0025] In some embodiments, the capacity surface density of the negative sheet is 3.3mAh / cm 2 to 11.5mAh / cm 2 The embodiments of the present application can balance the capacity and expansion of the negative sheet to some extent, and take into account the energy density and cycle performance of the cylindrical battery cell.

[0026] In some embodiments, the capacity surface density of the negative sheet is 3.96mAh / cm 2 to 7.56mAh / cm 2 The energy density and cycle performance of the cylindrical battery cell can be further taken into account.

[0027] In some embodiments, the gap extends along the winding direction of the electrode assembly, and the gap has a winding start end and a winding end end.

[0028] In some embodiments, the radial dimension of at least part of the gap is 5-60μm. Limiting the radial dimension W of at least part of the gap to be greater than or equal to 5μm can provide space for the expansion of the negative sheet, reduce the expansion force, improve the cycle performance of the cylindrical battery cell, and reduce the risk of deformation and cracking of the shell. The embodiments of the present application limit the radial dimension W of at least part of the gap to be less than or equal to 60μm to shorten the ion migration path between the positive and negative sheets, reduce the internal resistance of the cylindrical battery cell, reduce heat generation, and reduce the influence of the gap on the energy density.

[0029] In some embodiments, the radial dimension of the part of the gap near the winding start end is greater than or equal to the radial dimension of the part of the gap near the winding end end. The part of the gap near the winding start end has a larger radial dimension to provide more expansion space for the negative sheet in the middle of the electrode assembly, reduce the risk of collapse of the middle of the electrode assembly due to expansion, and improve the cycle performance of the cylindrical battery cell.

[0030] In some embodiments, the radial dimension of at least part of the gap gradually decreases along the winding direction. The radial dimension of the gap changes smoothly, reducing the sudden change in the radial dimension of the gap, reducing the stress concentration of the negative sheet, and improving the cycle performance of the battery cell.

[0031] In some embodiments, the gap includes a middle region and two end regions arranged along the axial direction of the cylindrical battery cell, the middle region is located between the two end regions, and the radial dimension of the middle region is smaller than the radial dimension of the end regions. The end regions have a larger radial dimension to facilitate the entry of electrolyte into the gap, improve the wettability of the electrolyte to the sheet, and improve the cycle performance of the cylindrical battery cell.

[0032] In some embodiments, the radial dimension of the gap gradually decreases in the direction from the end region to the middle region, so as to reduce the abrupt change of the radial dimension of the gap, reduce the stress concentration of the negative electrode sheet, and improve the cycle performance of the battery cell.

[0033] In some embodiments, the separator includes a base and a plurality of support portions, the support portions including organic particles disposed on the base. The organic particles can support the positive electrode sheet or the negative electrode sheet to increase the gap and provide space for the expansion of the negative electrode sheet.

[0034] In some embodiments, the base of the separator includes a base film and an inorganic particle layer disposed on the base film, and the organic particles at least partially protrude from the inorganic particle layer. The inorganic particle layer includes a plurality of inorganic particles, and gaps are formed between the inorganic particles and the organic particles, which are sufficient and unevenly distributed, so as to improve the air permeability of the separator and enable the cylindrical battery cell to have better cycle performance and reliability.

[0035] In some embodiments, the side of the positive electrode sheet facing the separator is provided with a plurality of support portions, the side of the separator facing the positive electrode sheet is provided with a plurality of support portions, and the plurality of support portions of the positive electrode sheet facing the separator and the plurality of support portions of the separator facing the positive electrode sheet are at least partially oppositely arranged. By oppositely arranging the plurality of support portions of the positive electrode sheet and the plurality of support portions of the separator, the plurality of support portions of the positive electrode sheet and the plurality of support portions of the separator can at least partially abut each other, so as to increase the gap and provide more space for the expansion of the negative electrode sheet.

[0036] In some embodiments, the side of the negative electrode sheet facing the separator is provided with a plurality of support portions, the side of the separator facing the negative electrode sheet is provided with a plurality of support portions, and the plurality of support portions of the negative electrode sheet facing the separator and the plurality of support portions of the separator facing the negative electrode sheet are at least partially oppositely arranged. By oppositely arranging the plurality of support portions of the negative electrode sheet and the plurality of support portions of the separator, the plurality of support portions of the negative electrode sheet and the plurality of support portions of the separator can at least partially abut each other, so as to increase the gap and provide more space for the expansion of the negative electrode sheet.

[0037] In some embodiments, the side of the negative electrode sheet facing the positive electrode sheet is provided with a plurality of support portions, the side of the positive electrode sheet facing the negative electrode sheet is provided with a plurality of support portions, and the plurality of support portions of the negative electrode sheet facing the positive electrode sheet and the plurality of support portions of the positive electrode sheet facing the negative electrode sheet are at least partially oppositely arranged. By oppositely arranging the plurality of support portions of the negative electrode sheet and the plurality of support portions of the positive electrode sheet, the plurality of support portions of the negative electrode sheet and the plurality of support portions of the positive electrode sheet can support each other, so as to increase the gap and provide more space for the expansion of the negative electrode sheet.

[0038] In some embodiments, the spacer is provided with a plurality of support portions on both sides. The gap includes a first gap formed between the positive sheet and the spacer and a second gap formed between the negative sheet and the spacer. By providing a plurality of support portions on both sides of the spacer, the gap can be increased, providing more space for the expansion of the negative sheet.

[0039] In some embodiments, one of the positive sheet and the negative sheet includes a first tab, and the other includes a second tab. The cylindrical battery cell includes a first electrode lead-out portion electrically connected to the first tab and a second electrode lead-out portion electrically connected to the second tab. In the axial direction of the cylindrical battery cell, the first electrode lead-out portion and the second electrode lead-out portion are located on the same side of the electrode assembly. When a plurality of cylindrical battery cells are assembled into a group, the first electrode lead-out portions and the second electrode lead-out portions of the plurality of cylindrical battery cells can be arranged on the same side, facilitating the connection of the current distribution member to the first electrode lead-out portions and the second electrode lead-out portions and simplifying the battery structure.

[0040] In some embodiments, the housing includes a shell and an end cover, the shell including an integrally formed side wall and an end wall, the side wall surrounding the electrode assembly, and the end wall and the end cover being opposite in the axial direction of the cylindrical battery cell, and the end cover being sealingly connected to the side wall.

[0041] In some embodiments, one of the positive sheet and the negative sheet includes a first tab, and the other includes a second tab. The cylindrical battery cell further includes an electrode terminal insulatively provided on the end wall, one of the first tab and the second tab being electrically connected to the electrode terminal, and the other being electrically connected to the end wall. The electrode terminal and the end wall can serve as two exposed electrodes of the cylindrical battery cell, and being located on the same side facilitates the assembly of a plurality of cylindrical battery cells into a group and simplifies the battery structure.

[0042] In some embodiments, the cylindrical battery cell further includes a first current collecting member located on the side of the first tab facing the end wall and connected to the first tab. The electrode terminal is abutted against and connected to the surface of the first current collecting member facing the end wall. The first current collecting member can serve as an adapter to achieve the electrical connection between the first tab and the electrode terminal.

[0043] In some embodiments, the electrode terminal is provided with a terminal recess on the side facing the first current collecting member, and / or the electrode terminal is provided with a terminal recess on the side facing away from the first current collecting member. The bottom wall of the terminal recess is welded to the first current collecting member. By providing the terminal recess, the thickness of the bottom wall of the terminal recess can be reduced, the power required for welding the electrode terminal and the first current collecting member from the outside can be reduced, the risk of particles generated by welding falling into the housing can be reduced, and the reliability of the cylindrical battery cell can be improved.

[0044] In some embodiments, the first and second tabs are both located at an end of the electrode assembly facing the end wall. The first and second tabs can share space in the axial direction, thereby improving space utilization and increasing energy density.

[0045] In some embodiments, the first tab is located at an end of the electrode assembly facing the end wall, and the second tab is located at an end of the electrode assembly facing the end cover. The cylindrical battery cell further includes a second current collecting member connected to the second tab; the second current collecting member is connected to at least one of the end cover and the side wall.

[0046] In some embodiments, the height of the shell is 1.3 to 4 times the diameter of the shell. When the shell meets the above size requirements, the structural stability of the shell is relatively high, and the use reliability of the cylindrical battery cell can be improved.

[0047] In some embodiments, the height of the shell is 50 to 150 mm.

[0048] In some embodiments, the diameter of the shell is 45 to 80 mm.

[0049] In some embodiments, the height of the shell is 50 to 150 mm.

[0050] In some embodiments, the diameter of the shell is 45 to 80 mm. BRIEF DESCRIPTION OF DRAWINGS

[0051] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can also be obtained by the drawings without creative labor for those skilled in the art.

[0052] FIG. 1 is a structural schematic diagram of a vehicle according to some embodiments of the present application;

[0053] FIG. 2 is an exploded schematic diagram of a battery according to some embodiments of the present application;

[0054] FIG. 3 is a structural schematic diagram of a battery module shown in FIG. 2;

[0055] FIG. 4 is a structural schematic diagram of a cylindrical battery cell according to some embodiments of the present application;

[0056] FIG. 5 is an exploded schematic diagram of the cylindrical battery cell shown in FIG. 4;

[0057] FIG. 6 is a cross-sectional schematic diagram of an electrode assembly of a cylindrical battery cell according to some embodiments of the present application;

[0058] FIG. 7 is an enlarged view of the area A in FIG. 6;

[0059] FIG. 8 is a schematic view of a separator of an electrode assembly of a cylindrical battery cell according to some embodiments of the present application;

[0060] FIG. 9 is a partial cross-sectional view of an electrode assembly of a cylindrical battery cell according to some other embodiments of the present application;

[0061] FIG. 10 is a schematic view of a separator of an electrode assembly of a cylindrical battery cell according to some other embodiments of the present application;

[0062] FIG. 11 is a partial cross-sectional view of an electrode assembly of a cylindrical battery cell according to some other embodiments of the present application;

[0063] FIG. 12 is a schematic view of a positive electrode sheet of an electrode assembly according to some embodiments of the present application, in a flattened state;

[0064] FIG. 13 is a cross-sectional view of a positive electrode sheet of an electrode assembly according to some embodiments of the present application;

[0065] FIG. 14 is a cross-sectional view of a negative electrode sheet of an electrode assembly according to some embodiments of the present application;

[0066] FIG. 15 is a cross-sectional view of a positive electrode sheet according to some other embodiments of the present application;

[0067] FIG. 16 is a cross-sectional view of a negative electrode sheet according to some other embodiments of the present application;

[0068] FIG. 17 is a partial cross-sectional view of an electrode assembly of a cylindrical battery cell according to some other embodiments of the present application;

[0069] FIG. 18 is a partial cross-sectional view of an electrode assembly of a cylindrical battery cell according to some other embodiments of the present application;

[0070] FIG. 19 is a cross-sectional view of the battery cell shown in FIG. 4;

[0071] FIG. 20 is an enlarged view of the area in circle in FIG. 19;

[0072] FIG. 21 is a partial cross-sectional view of a battery cell according to some other embodiments of the present application.

[0073] In the drawings, the drawings are not necessarily drawn to scale.

[0074] Reference signs are explained as follows:

[0075] 1, vehicle; 2, battery; 3, controller; 4, motor; 5, case; 5a, first case portion; 5b, second case portion; 5c, accommodation space; 6, battery module; 7, cylindrical battery cell; 7a, first electrode lead-out portion; 7b, second electrode lead-out portion;

[0076] 10, electrode assembly; 10a, first tab; 10b, second tab; 10c, electrode main body;

[0077] 11, positive electrode sheet; 111, positive electrode base; 112, positive electrode protrusion; 113, positive electrode recess; 11a, positive electrode current collector; 11b, positive electrode film layer; 11c, positive electrode particle coating;

[0078] 12, negative electrode sheet; 121, negative electrode base; 122, negative electrode protrusion; 123, negative electrode recess; 12a, negative electrode current collector; 12b, negative electrode film layer; 12c, negative electrode particle coating;

[0079] 13, separator; 131, separator base; 13a, base film; 13b, coating layer;

[0080] 14, support portion; 141, first support portion; 142, second support portion;

[0081] 15, base; 151, first surface;

[0082] 20, housing; 21, case; 211, end wall; 212, side wall; 22, end cap;

[0083] 30, electrode terminal; 31, terminal recess; 32, through-hole;

[0084] 40, first current collecting member; 50, cover plate; 60, second current collecting member;

[0085] G, gap; G1, first gap; G2, second gap;

[0086] C1, middle region; C2, end region; C3, transition region;

[0087] E1, winding start end; E2, winding end end; E3, positive electrode winding start end; E4, positive electrode winding end end; E5, negative electrode winding start end; E6, negative electrode winding end end; E7, first end; E8, second end;

[0088] P, organic particle; P1, first organic particle; P2, second organic particle; P3, inorganic particle layer;

[0089] V, winding direction; Z, axial direction. DETAILED DESCRIPTION

[0090] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0091] Unless otherwise defined, all technical and scientific terms used in the present application have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs; the terms used in the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application; the terms "include" and "have" and any variations thereof in the specification and claims of the present application and the above description of drawings are intended to cover non-exclusive inclusion. The terms "first", "second" and the like in the specification and claims of the present application and the above description of drawings are used to distinguish different objects, not to describe a particular order or primary and secondary relationship.

[0092] In the present application, the phrase "embodiments" means that the specific features, structures or characteristics described in connection with the embodiments can be included in at least one embodiment of the present application. The phrase appears at various places in the specification does not necessarily all refer to the same embodiments, nor are they necessarily mutually exclusive or alternative embodiments to each other.

[0093] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mount", "connect", "connection", "attach" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral connection; it can be direct connection, or indirect connection through intermediate medium; it can be internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0094] In the present application, the term "and / or" is only a description of the association relationship between the associated objects, which means that there can be three kinds of relationships, for example, A and / or B can mean that A exists alone, A and B exist together, and B exists alone. In addition, the character " / " in the present application generally represents a "or" relationship between the front and rear associated objects.

[0095] In the embodiments of the present application, the same reference signs represent the same parts, and for the sake of brevity, the detailed description of the same parts is omitted in different embodiments. It should be understood that the thickness, length and width of various components in the embodiments of the present application shown in the drawings, and the overall thickness, length and width of the integrated device are only exemplary and should not constitute any limitation on the present application.

[0096] As used herein, "a plurality" means two or more (including two).

[0097] The cylindrical battery cell can be a cylindrical secondary battery, which refers to a battery cell that can be activated by charging after discharging to continue use.

[0098] The battery can refer to a single physical module including one or more cylindrical battery cells to provide higher voltage and capacity.

[0099] The cylindrical battery cell generally includes an electrode assembly and a case for accommodating the electrode assembly. The electrode assembly generally includes a positive electrode sheet, a negative electrode sheet, and a separator that separates the positive electrode sheet and the negative electrode sheet.

[0100] During the cyclic charging and discharging of the cylindrical battery cell, the negative electrode sheet swells due to the insertion of ions; as the diameter of the cylindrical battery cell increases, the swelling amount of the negative electrode sheet accumulates and can generate a greater swelling force, which can increase the pressure between the positive electrode sheet and the negative electrode sheet, causing the electrolyte in the internal pores of the positive electrode film layer of the positive electrode sheet and the electrolyte in the internal pores of the negative electrode film layer of the negative electrode sheet to be squeezed out, affecting the cycle performance of the cylindrical battery cell.

[0101] In addition, the swollen electrode assembly also squeezes the case, which can cause the case to deform or even break, affecting the reliability of the cylindrical battery cell.

[0102] In view of this, the embodiments of the present application provide a technical solution, in which at least one of the positive electrode sheet, the negative electrode sheet, and the separator is provided with a plurality of support portions to form a gap between the positive electrode sheet and the negative electrode sheet, the gap can provide space for the swelling of the negative electrode sheet, thereby reducing the swelling force, improving the cycle performance of the cylindrical battery cell, and improving the reliability of the cylindrical battery cell.

[0103] The cylindrical battery cell described in the embodiments of the present application is suitable for a battery and an electric device using the battery.

[0104] The electric device disclosed in the embodiments of the present application can be a device using a battery as a power source or a variety of energy storage systems using a battery as an energy storage element. The electric device can be, but is not limited to, a mobile phone, a tablet, a notebook computer, an electric toy, an electric tool, an electric vehicle, an electric car, a ship, a spacecraft, etc. Among them, the electric toy can include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric plane toy, etc., and the spacecraft can include an airplane, a rocket, a space shuttle, a spacecraft, etc.

[0105] The following embodiments are described by taking a vehicle as an example for convenience of description.

[0106] FIG. 1 is a structural schematic diagram of a vehicle according to some embodiments of the present application.

[0107] As shown in FIG. 1, the vehicle 1 is internally provided with a battery 2, which can be arranged at the bottom, head or tail of the vehicle 1. The battery 2 can be used for power supply of the vehicle 1, for example, the battery 2 can be used as the operating power source of the vehicle 1.

[0108] The vehicle 1 can further include a controller 3 and a motor 4, the controller 3 being used to control the battery 2 to supply power to the motor 4, for example, for the power demand of the vehicle 1 during starting, navigation and driving.

[0109] In some embodiments of the present application, the battery 2 can not only be used as the operating power source of the vehicle 1, but also be used as the driving power source of the vehicle 1, replacing or partially replacing the fuel or natural gas to provide driving power for the vehicle 1.

[0110] FIG. 2 is an exploded schematic diagram of the battery according to some embodiments of the present application. As shown in FIG. 2, the battery 2 includes a box body 5 and a cylindrical battery cell (not shown in FIG. 2), and the cylindrical battery cell is contained in the box body 5.

[0111] The box body 5 is used to contain the cylindrical battery cell, and the box body 5 can have various structures. In some embodiments, the box body 5 can include a first box body part 5a and a second box body part 5b, the first box body part 5a and the second box body part 5b are mutually covered, and the first box body part 5a and the second box body part 5b jointly define a containing space 5c for containing the cylindrical battery cell. The second box body part 5b can be a hollow structure with one end open, and the first box body part 5a is a plate-like structure, which is covered on the open side of the second box body part 5b to form the box body 5 with the containing space 5c; or the first box body part 5a and the second box body part 5b can both be a hollow structure with one side open, and the open side of the first box body part 5a is covered on the open side of the second box body part 5b to form the box body 5 with the containing space 5c. Of course, the first box body part 5a and the second box body part 5b can have various shapes, such as a cylinder, a cuboid, etc.

[0112] In order to improve the sealing performance of the first box body part 5a and the second box body part 5b after being connected, a sealing member such as sealing glue, sealing ring, etc. can be arranged between the first box body part 5a and the second box body part 5b.

[0113] Supposing that the first box body part 5a is covered on the top of the second box body part 5b, the first box body part 5a can also be referred to as an upper box cover, and the second box body part 5b can also be referred to as a lower box body.

[0114] In the battery 2, the cylindrical battery cell can be one or multiple. If the cylindrical battery cell is multiple, the multiple cylindrical battery cells can be connected in series, in parallel or in a mixed manner. The mixed manner means that the multiple cylindrical battery cells are connected in series and in parallel. The multiple cylindrical battery cells can be directly connected in series, in parallel or in a mixed manner, and the whole of the multiple cylindrical battery cells is accommodated in the box 5. Of course, the multiple cylindrical battery cells can be first connected in series, in parallel or in a mixed manner to form a battery module 6, and the multiple battery modules 6 are connected in series, in parallel or in a mixed manner to form a whole, and the whole is accommodated in the box 5.

[0115] The cylindrical battery cell can be the smallest unit of the battery.

[0116] In some embodiments, the box 5 can be part of the chassis structure of the vehicle. For example, part of the box 5 can be at least part of the floor of the vehicle, or part of the box 5 can be at least part of the cross beam and the longitudinal beam of the vehicle.

[0117] In some embodiments, the battery 2 can be an energy storage device. The energy storage device includes an energy storage container, an energy storage cabinet and the like.

[0118] FIG. 3 is a structural schematic diagram of the battery module shown in FIG. 2.

[0119] In some embodiments, as shown in FIG. 3, the cylindrical battery cell 7 is multiple, and the multiple cylindrical battery cells 7 are first connected in series, in parallel or in a mixed manner to form a battery module 6. The multiple battery modules 6 are connected in series, in parallel or in a mixed manner to form a whole, and the whole is accommodated in the box.

[0120] The multiple cylindrical battery cells 7 in the battery module 6 can be electrically connected through a busbar component to realize the parallel connection, the series connection or the mixed connection of the multiple cylindrical battery cells 7 in the battery module 6. The busbar component can be one or multiple, and each busbar component is used to electrically connect at least two cylindrical battery cells 7.

[0121] The cylindrical battery cell 7 can be a lithium ion battery cell, a sodium ion battery cell, a sodium lithium ion battery cell, a lithium metal battery cell, a sodium metal battery cell, a lithium sulfur battery cell, a magnesium ion battery cell, a nickel hydrogen battery cell, a nickel cadmium battery cell, a lead-acid battery cell and the like.

[0122] FIG. 4 is a structural schematic diagram of a cylindrical battery cell in some embodiments of the present application; FIG. 5 is an exploded schematic diagram of the cylindrical battery cell shown in FIG. 4; FIG. 6 is a sectional view schematic diagram of an electrode assembly of the cylindrical battery cell provided in some embodiments of the present application; FIG. 7 is an enlarged schematic diagram of the dashed box A in FIG. 6; and FIG. 8 is a schematic diagram of a separator of the electrode assembly of the cylindrical battery cell provided in some embodiments of the present application.

[0123] Referring to FIGS. 4-8, the embodiments of the present application provide a cylindrical battery cell 7, which includes a housing 20 and an electrode assembly 10, at least a portion of the electrode assembly 10 being accommodated in the housing 20.

[0124] The housing 20 is a hollow structure, and an accommodation space for accommodating the electrode assembly 10 and electrolyte is formed inside the housing 20. The housing 20 of the cylindrical battery cell 7 is a cylindrical housing.

[0125] As an example, the housing 20 includes a shell 21 having an opening and an end cap 22 for covering the opening.

[0126] The shell 21 is a component for cooperating with the end cap 22 to form an internal cavity of the cylindrical battery cell 7, and the internal cavity formed can be used to accommodate the electrode assembly 10, electrolyte and other components.

[0127] The shell 21 and the end cap 22 can be independent components. As an example, the opening can be provided on the shell 21, and the internal cavity of the cylindrical battery cell 7 can be formed by covering the opening with the end cap 22.

[0128] The shell 21 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.

[0129] The shape of the end cap 22 can be adapted to the shape of the shell 21 to cooperate with the shell 21. The material of the end cap 22 can be the same as or different from the material of the shell 21. Alternatively, the end cap 22 can be made of a material having certain hardness and strength (such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.), so that the end cap 22 is not easily deformed when subjected to extrusion and impact, and the cylindrical battery cell 7 can have higher structural strength and improved reliability.

[0130] The end cap 22 is connected to the shell 21 by welding, bonding, clamping or other means.

[0131] The shell 21 can be open at one end or both ends. In some examples, the shell 21 can be a structure open at one side, and the end cap 22 is provided as one and covers the shell 21. In other examples, the shell 21 can also be a structure open at both sides, and the end cap 22 is provided as two and covers the two openings of the shell 21.

[0132] In some embodiments, the shell 21 includes an integral side wall 212 and an end wall 211, the end wall 211 and the end cap 22 are opposite along the axial direction Z of the cylindrical battery cell, and the end cap 22 is sealingly connected to the side wall 212.

[0133] The electrode assembly 10 is a component in which electrochemical reactions occur in the cylindrical battery cell 7. The electrode assembly 10 can be housed entirely within the case 20, or can be housed partially within the case 20. For example, a portion of the tab of the electrode assembly 10 can extend outside the case 20.

[0134] Optionally, the electrode assembly 10 is housed entirely within the case 20.

[0135] In some embodiments, the diameter of the cylindrical battery cell is greater than or equal to 40 mm. A large-diameter cylindrical battery cell has a high capacity, which is advantageous in increasing the energy density when a plurality of cylindrical battery cells are assembled into a group.

[0136] In some embodiments, the electrode assembly 10 includes a positive electrode sheet 11 and a negative electrode sheet 12. During charging and discharging of the cylindrical battery cell 7, active ions (e.g., lithium ions) are intercalated and deintercalated between the positive electrode sheet 11 and the negative electrode sheet 12.

[0137] In some embodiments, the positive electrode sheet 11 can include a positive electrode current collector and a positive electrode film layer disposed on at least one surface of the positive electrode current collector.

[0138] As an example, the positive electrode current collector has two surfaces opposite in the thickness direction thereof, and the positive electrode film layer is disposed on either one or both of the two opposite surfaces of the positive electrode current collector.

[0139] As an example, the positive electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, silver surface-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, a carbon electrode, carbon, nickel, or titanium, or the like can be used. The composite current collector can include a high molecular material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, or the like) on a high molecular material base material (e.g., a base material of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, or the like).

[0140] As an example, the positive electrode film layer includes a positive electrode active material, which may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxides include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.80 Co 0.15 Al 0.05 At least one of O2 and its modified compounds.

[0141] In some embodiments, the negative electrode 12 may include a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector.

[0142] As an example, the negative current collector can employ a metal foil, a foamed metal, a foamed carbon, or a composite current collector. For example, as the metal foil, silver surface-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, a carbon electrode, or the like can be employed. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or the like. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, or the like) on a polymer material base material (a base material of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, or the like).

[0143] As an example, the negative current collector has two surfaces opposite in the thickness direction thereof, and the negative film layer is provided on either one or both of the two opposite surfaces of the negative current collector.

[0144] As an example, the negative film layer includes a negative active material. For example, the negative active material can include at least one of artificial graphite, natural graphite, soft carbon, hard carbon, a silicon-based material, a tin-based material, lithium titanate, or the like. The silicon-based material can be selected from at least one of elemental silicon, a silicon oxide compound, a silicon-carbon composite, a silicon-nitrogen composite, and a silicon alloy. The tin-based material can be selected from at least one of elemental tin, a tin oxide compound, and a tin alloy. However, the present application is not limited to these materials, and other conventional materials that can be used as a battery negative active material can also be used. These negative active materials can be used alone or in combination of two or more.

[0145] In some embodiments, the material of the positive current collector can be aluminum, and the material of the negative current collector can be copper.

[0146] In some embodiments, the electrode assembly 10 further includes a separator 13 provided between the positive sheet 11 and the negative sheet 12. The separator 13 can function to prevent short circuiting of the positive and negative electrodes, while allowing the passage of active ions.

[0147] In some embodiments, the cylindrical battery cell 7 further includes an electrolyte that functions to conduct ions between the positive sheet 11 and the negative sheet 12. The electrolyte can be in a liquid state, a gel state, or a solid state.

[0148] In some embodiments, the liquid electrolyte includes an electrolyte salt and a solvent.

[0149] As an example, the electrolyte salt can be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonylimide, lithium bistrifluoromethylsulfonylimide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluoroboric oxalate, lithium bioricoboric, lithium difluoroboric dioxalate, and lithium tetrafluorophosphoric oxalate.

[0150] As an example, the solvent can be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, butyl sulfone, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent can also be selected from an ether-based solvent. The ether-based solvent can include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and a crown ether.

[0151] In some embodiments, the gel-state electrolyte includes a polymer as a backbone network of the electrolyte, in combination with an ionic liquid-lithium salt.

[0152] In some embodiments, the solid-state electrolyte includes a polymer solid-state electrolyte, an inorganic solid-state electrolyte, a composite solid-state electrolyte.

[0153] As an example, the polymer solid-state electrolyte can be a polyether (polyethylene oxide), a polysiloxane, a polycarbonate, a polyacrylonitrile, a polyvinylidene fluoride, a polymethyl methacrylate, a single-ion polymer, a polyionic liquid-lithium salt, a cellulose, or the like.

[0154] As an example, the inorganic solid-state electrolyte can be one or more of an oxide solid electrolyte (crystalline perovskite, sodium superionic conductor, garnet, amorphous LiPON thin film), a sulfide solid electrolyte (crystalline lithium superionic conductor (lithium germanium phosphorous sulfide, argyrodite), amorphous sulfide), and a halide solid electrolyte, a nitride solid electrolyte, and a hydride solid electrolyte.

[0155] As an example, the composite solid-state electrolyte is formed by adding an inorganic solid-state electrolyte filler to a polymer solid-state electrolyte.

[0156] In some embodiments, the positive electrode sheet 11, the negative electrode sheet 12, and the separator 13 are wound.

[0157] The electrode assembly 10 is a wound structure. As an example, the positive electrode sheet 11, the separator 13, and the negative electrode sheet 12 are wound into a cylindrical wound structure.

[0158] In some embodiments, the diameter of the cylindrical battery cell 7 is greater than or equal to 40 mm. The cylindrical battery cell 7 includes a housing 20 and an electrode assembly 10, at least a portion of which is accommodated in the housing 20.

[0159] As an example, the diameter of the housing is greater than or equal to 40 mm.

[0160] The electrode assembly 10 includes a positive electrode sheet 11, a negative electrode sheet 12, and a separator 13, which are wound together, and the separator 13 separates the positive electrode sheet 11 and the negative electrode sheet 12.

[0161] The negative electrode active material of the negative electrode sheet 12 includes at least one of a silicon-based material and a carbon-based material.

[0162] At least one of the positive electrode sheet 11, the negative electrode sheet 12, and the separator 13 includes a base 15 and a plurality of support portions 14 provided to the base 15. The base 15 has two first surfaces 151 oppositely disposed along a thickness direction thereof, and the plurality of support portions 14 are protruded from at least one of the first surfaces 151 to form a gap G between the positive electrode sheet 11 and the negative electrode sheet 12.

[0163] As an example, the carbon-based material includes at least one of artificial graphite and natural graphite.

[0164] As an example, the silicon-based material includes at least one of elemental silicon, a silicon oxide compound, a silicon-carbon composite, a silicon-nitrogen composite, and a silicon alloy.

[0165] As an example, the plurality of support portions 14 are dispersedly arranged on the first surface 151.

[0166] In some examples, one of the first surfaces 151 of the base 15 is provided with the plurality of support portions 14. Of course, the first surface 151 of the base 15 can be inwardly radially provided with the plurality of support portions 14, or the first surface 151 of the base 15 can be outwardly radially provided with the plurality of support portions 14.

[0167] In other examples, both of the first surfaces 151 of the base 15 are provided with the plurality of support portions 14.

[0168] In the electrode assembly 10, one of the positive electrode sheet 11, the negative electrode sheet 12, and the separator 13 can be provided with the support portions 14, both of them can be provided with the support portions 14, or all of them can be provided with the support portions 14.

[0169] In some examples, the positive electrode sheet 11 includes a base and a plurality of support portions, and for the convenience of description, the base of the positive electrode sheet 11 can be referred to as a positive electrode base. Optionally, the negative electrode sheet 12 and the separator 13 can be provided with the support portions or can not be provided with the support portions. In the plurality of support portions of the positive electrode sheet 11, some of the support portions can be in contact with the separator, or all of the support portions can be in contact with the separator.

[0170] In some examples, the negative electrode sheet 12 includes a base and a plurality of support portions, and the base of the negative electrode sheet can be referred to as a negative electrode base for ease of description. Optionally, the positive electrode sheet 11 and the separator 13 can be provided with support portions or can not be provided with support portions. In the plurality of support portions of the negative electrode sheet 12, some of the support portions can be in contact with the separator or all of the support portions can be in contact with the separator.

[0171] In some examples, the separator 13 includes a base 15 and a plurality of support portions 14, and the base of the separator 13 can be referred to as a separator base 131 for ease of description. Optionally, the positive electrode sheet 11 and the negative electrode sheet 12 can be provided with support portions or can not be provided with support portions. As an example, the positive electrode sheet 11 can be in contact with some of the support portions of the separator 13, and / or the negative electrode sheet 12 can be in contact with some of the support portions of the separator 13.

[0172] As an example, the gap G can be a space between the positive electrode sheet 11 and the negative electrode sheet 12 that is not filled by the separator 13.

[0173] The support portions 14 can be rigid or flexible.

[0174] In some examples, at least two of the positive electrode sheet 11, the negative electrode sheet 12, and the separator 13 are provided with support portions 14, and the support portions 14 of the two can be formed in the same manner or in different manners.

[0175] The plurality of support portions 14 protrude and can support at least one of the positive electrode sheet 11 and the negative electrode sheet 12, thereby forming a gap G between the positive electrode sheet 11 and the negative electrode sheet 12. During the cycling of the cylindrical battery cell 7, the gap G can provide space for the expansion of the negative electrode sheet 12, reduce the pressure between the positive electrode sheet 11 and the negative electrode sheet 12, thereby reducing the compression of the electrolyte in the internal pores of the positive electrode film layer of the positive electrode sheet 11 and the internal pores of the negative electrode film layer of the negative electrode sheet 12, can reduce the concentration difference of the electrolyte in each region inside the electrode sheet, and improve the cycling performance of the cylindrical battery cell 7 with a larger diameter. The gap G can reduce the expansion amount of the electrode assembly 10, thereby reducing the compression effect on the shell 20, reducing the risk of deformation and cracking of the shell 20, and improving the reliability of the cylindrical battery cell 7. By providing the gap G, the increase in the expansion force caused by increasing the diameter of the cylindrical battery cell 7 can be reduced, the diameter of the cylindrical battery cell 7 can be increased, and the capacity of the cylindrical battery cell 7 can be improved.

[0176] The gap G can also accommodate electrolyte to improve the wettability of the electrolyte to the positive electrode sheet and the negative electrode sheet and improve the cycling performance of the cylindrical battery cell.

[0177] In addition, when ion precipitation occurs in the negative electrode sheet 12 during cycling, such as lithium precipitation, the gap G can provide space for deformation of the spacer 13, so that the spacer 13 can release the pressure exerted by lithium dendrites through deformation, thereby avoiding the risk of the spacer 13 being pierced, reducing the risk of short circuit, and improving reliability.

[0178] In some embodiments, the negative active material includes a carbon-based material. The carbon-based material has high cycle stability, which can improve the cycle performance of the cylindrical battery cell.

[0179] In some embodiments, the support portion 14 is configured to be compressible. During cycling of the cylindrical battery cell 7, the support portion 14 can be compressed when pressed, thereby providing more expansion space for the negative electrode sheet 12. The compressible support portion 14 can release stress through compression deformation to reduce the risk of the positive electrode sheet 11 or the negative electrode sheet 12 being bruised by the support portion 14, thereby improving reliability.

[0180] In some embodiments, the plurality of support portions 14 includes a first support portion 141 and a second support portion 142, and the height H1 at which the first support portion 141 protrudes from the first surface 151 is greater than the height H2 at which the second support portion 142 protrudes from the first surface 151.

[0181] The first support portion 141 can be one or more. The second support portion 142 can be one or more. Alternatively, both the first support portion 141 and the second support portion 142 are multiple.

[0182] The first support portion 141 has a greater height, which can support the positive electrode sheet 11 or the negative electrode sheet 12 to form a larger gap G, thereby providing more space for the expansion of the negative electrode sheet 12. The second support portion 142 has a smaller height, and occupies less space. As the negative electrode sheet 12 expands, the gap G gradually decreases; the second support portion 142 can be pressed after the negative electrode sheet 12 expands to a certain extent, which can reduce the pressure on the negative electrode sheet 12 in the early stage of expansion. When the second support portion 142 is pressed, the second support portion 142 can slow down the expansion of the negative electrode sheet 12 to some extent, reduce the electrolyte squeezed out by the negative electrode sheet 12, and improve the cycle performance of the cylindrical battery cell 7.

[0183] In some embodiments, the first support portion 141 is multiple, and the second support portion 142 is multiple.

[0184] In some embodiments, the height of the first support portion 141 is 1.1 to 15 times, and optionally 2 to 7 times, the height of the second support portion 142.

[0185] In some embodiments, the separator 13 comprises a separator base 131 and a plurality of support portions 14. Optionally, the plurality of support portions 14 of the separator 13 comprises a first support portion 141 and a second support portion 142.

[0186] In some embodiments, at least one of the positive electrode sheet 11, the negative electrode sheet 12 and the separator 13 comprises a plurality of organic particles P, and the support portion 14 comprises the organic particles P.

[0187] Exemplarily, in the electrode assembly 10, one of the positive electrode sheet 11, the negative electrode sheet 12 and the separator 13 can be provided with the organic particles P, both of them can be provided with the organic particles P, or all of them can be provided with the organic particles P.

[0188] The organic particles P can play a supporting role to form the gap G. When the cylindrical battery cell 7 appears thermal runaway, the organic particles P can form a gel film structure at high temperature, thereby reducing the diffusion channel of active ions and delaying the time of thermal spread, so as to improve the reliability of the cylindrical battery cell 7.

[0189] Exemplarily, the organic particles P can be formed on the positive electrode sheet 11, the negative electrode sheet 12 or the separator 13 by coating. The support portion 14 formed by coating the organic particles P can simplify the forming process.

[0190] In some embodiments, the plurality of organic particles P comprises first organic particles P1 and second organic particles P2, and the number average particle size of the first organic particles P1 is greater than that of the second organic particles P2.

[0191] It should be noted that the number average particle size of the organic particles is the arithmetic mean of the particle size of the organic particles counted by the number of the organic particles. The particle size of the organic particles can refer to the distance between the two most distant points on the organic particles.

[0192] The first organic particles P1 with a larger number average particle size can support the positive electrode sheet 11 or the negative electrode sheet 12 to form a larger gap G, thereby providing more space for the expansion of the negative electrode sheet 12. The second organic particles P2 with a smaller number average particle size can be compressed after the negative electrode sheet 12 expands to a certain extent, which can reduce the pressure on the negative electrode sheet 12 in the initial stage of expansion. When the second organic particles P2 are compressed, the second organic particles P2 can slow down the expansion of the negative electrode sheet 12 to a certain extent, reduce the electrolyte squeezed out by the negative electrode sheet 12, and improve the cycle performance of the cylindrical battery cell 7.

[0193] In some embodiments, the plurality of support portions 14 includes a first support portion 141 and a second support portion 142, the first support portion 141 protruding from the first surface by a height greater than a height by which the second support portion 142 protrudes from the first surface. The organic particles P include first organic particles P1 and second organic particles P2; the first support portion 141 includes the first organic particles P1, and the second support portion 142 includes the second organic particles P2.

[0194] By providing the first organic particles P1 and the second organic particles P2 having different number average particle diameters, the first support portion 141 and the second support portion 142 having different heights can be formed. The first support portion 141 has a greater height, which can support the positive electrode sheet 11 or the negative electrode sheet 12 to form a larger gap G, thereby providing more space for the expansion of the negative electrode sheet 12. The second support portion 142 can be compressed after the negative electrode sheet 12 expands to a certain extent, which can reduce the pressure on the negative electrode sheet 12 in the initial stage of expansion. When the second support portion 142 is compressed, the second support portion 142 can slow down the expansion of the negative electrode sheet 12 to some extent, reduce the electrolyte squeezed out by the negative electrode sheet 12, and improve the cycle performance of the cylindrical battery cell 7.

[0195] In some embodiments, the number average particle diameter of the first organic particles P1 is > 10 pm, and the number average particle diameter of the second organic particles P2 is 2 pm-10 pm.

[0196] In some embodiments, the number average particle diameter of the first organic particles P1 is 12 pm-25 pm. For example, the number average particle diameter of the first organic particles P1 can be 12 pm, 13 pm, 15 pm, 16 pm, 18 pm, 20 pm, 21 pm, 22 pm, 24 pm, or 25 pm.

[0197] In some embodiments, the number average particle diameter of the second organic particles P2 is 2 pm-9 pm. For example, the number average particle diameter of the first organic particles P1 can be 2 pm, 2.5 pm, 3 pm, 4 pm, 5 pm, 5.5 pm, 6 pm, 7 pm, 8 pm, or 9 pm.

[0198] In some embodiments, the ratio of the number average particle diameter of the first organic particles P1 to the number average particle diameter of the second organic particles P2 is greater than or equal to 1.5.

[0199] In some embodiments, the first organic particles P1 are secondary particles.

[0200] In some embodiments, the second organic particles P2 are primary particles.

[0201] It should be noted that primary particles and secondary particles have meanings known in the art. Primary particles refer to particles that are not in an agglomerated state. Secondary particles refer to agglomerated particles formed by the aggregation of two or more primary particles.

[0202] In some embodiments, the plurality of organic particles P includes first organic particles P1 including one or more of a homopolymer or copolymer of a fluorine-containing vinylic monomer unit, a homopolymer or copolymer of an olefinic monomer unit, a homopolymer or copolymer of an unsaturated nitrile monomer unit, a homopolymer or copolymer of an alkylene oxide monomer unit, and a modified compound of each of the above homopolymers or copolymers.

[0203] In some embodiments, the fluorine-containing vinylic monomer unit can be selected from one or more of difluoroethylene, vinylidene fluoride, trifluoroethylene, chlorotrifluoroethylene, tetrafluoroethylene, hexafluoropropylene.

[0204] In some embodiments, the olefinic monomer unit can be selected from one or more of ethylene, propylene, butadiene, isoprene, and the like.

[0205] In some embodiments, the unsaturated nitrile monomer unit can be selected from one or more of acrylonitrile, methacrylonitrile, and the like.

[0206] In some embodiments, the alkylene oxide monomer unit can be selected from one or more of ethylene oxide, propylene oxide, and the like.

[0207] In some embodiments, the first organic particles P1 include one or more of polytetrafluoroethylene, polychlorotrifluoroethylene, polyfluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyacrylonitrile, polyethylene oxide, a copolymer of different fluorine-containing vinylic monomer units, a copolymer of a fluorine-containing vinylic monomer unit and an olefinic monomer unit, a copolymer of a fluorine-containing vinylic monomer unit and an acrylic monomer unit, a copolymer of a fluorine-containing vinylic monomer unit and an acrylate monomer unit, and a modified compound of each of the above homopolymers or copolymers.

[0208] In some embodiments, the first organic particles P1 can include one or more of a vinylidene fluoride-trifluoroethylene copolymer, a vinylidene fluoride-hexafluoropropylene copolymer, a vinylidene fluoride-trifluoroethylene-hexafluoropropylene copolymer, a vinylidene fluoride-hexafluoropropylene-acrylic acid copolymer, a vinylidene fluoride-hexafluoropropylene-acrylate copolymer, and a modified compound of each of the above copolymers.

[0209] In some embodiments, the plurality of organic particles P includes second organic particles P2 including one or more of a homopolymer or copolymer of an acrylate monomer unit, a homopolymer or copolymer of an acrylic monomer unit, a homopolymer or copolymer of a styrene monomer unit, a polyurethane compound, a rubber compound, and a modified compound of each of the above homopolymers or copolymers.

[0210] In some embodiments, the second organic particles P2 include one or several of a copolymer of an acrylate monomer unit and a styrene monomer unit, a copolymer of an acrylic monomer unit and a styrene monomer unit, a copolymer of an acrylic monomer unit-acrylate monomer unit-styrene monomer unit, a copolymer of a styrene monomer unit and an unsaturated nitrile monomer unit, a copolymer of a styrene monomer unit-olefin monomer unit-unsaturated nitrile monomer unit, and modified compounds of the above copolymers.

[0211] In some embodiments, the acrylate monomer unit can be selected from one or several of methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, methyl methacrylate, butyl methacrylate, isooctyl methacrylate, and the like.

[0212] In some embodiments, the acrylic monomer unit can be selected from one or several of acrylic acid, methacrylic acid, and the like.

[0213] In some embodiments, the styrene monomer unit can be selected from one or several of styrene, methylstyrene, and the like.

[0214] In some embodiments, the unsaturated nitrile monomer unit can be selected from one or several of acrylonitrile, methacrylonitrile, and the like.

[0215] In some embodiments, the second organic particles P2 can include one or several of a butyl acrylate-styrene copolymer, a butyl methacrylate-isooctyl methacrylate copolymer, an isooctyl methacrylate-styrene copolymer, a methacrylate-methacrylic acid-styrene copolymer, a methyl acrylate-isooctyl methacrylate-styrene copolymer, a butyl acrylate-isooctyl acrylate-styrene copolymer, a butyl acrylate-isooctyl methacrylate-styrene copolymer, a butyl methacrylate-isooctyl acrylate-styrene copolymer, a butyl methacrylate-isooctyl methacrylate-styrene copolymer, a styrene-acrylonitrile copolymer, a styrene-butadiene-acrylonitrile copolymer, a methyl acrylate-styrene-acrylonitrile copolymer, an isooctyl methacrylate-styrene-acrylonitrile copolymer, a styrene-vinyl acetate copolymer, a styrene-vinyl acetate-pyrrolidone copolymer, and modified compounds of the above materials.

[0216] In some embodiments, the spacer 13 includes a base 15 and a plurality of support portions 14 including organic particles disposed on the base.

[0217] The organic particles P can project in their entirety from the base 15. Alternatively, a portion of the organic particles is embedded in the base 15 and another portion projects from the base 15.

[0218] The organic particles P can support the positive electrode sheet 11 or the negative electrode sheet 12 to increase the gap G and provide space for expansion of the negative electrode sheet 12.

[0219] For simplicity of description, the base 15 of the separator 13 can be referred to as a separator base 131.

[0220] In some embodiments, the base 15 of the separator 13 includes a base film 13a and an inorganic particle layer P3 disposed on the base film 13a, and the organic particles P at least partially protrude from the inorganic particle layer P3.

[0221] The inorganic particle layer P3 includes a plurality of inorganic particles, and the inorganic particles and the organic particles form sufficient and unevenly distributed voids therebetween, which can improve the air permeability of the separator and provide the cylindrical battery cell with better cycle performance and reliability.

[0222] In some embodiments, the separator 13 includes a coating layer 13b disposed on at least one surface of the base film 13a. The coating layer 13b includes the inorganic particle layer P3 and the plurality of organic particles P.

[0223] In some examples, the inorganic particles can be coated on the base film 13a to form the inorganic particle layer P3 first, and then the plurality of organic particles can be coated on the inorganic particle layer P3. In other examples, the inorganic particles and the organic particles can be mixed together and then coated on the base film 13a.

[0224] In some examples, one surface of the base film 13a is coated with the coating layer 13b including the inorganic particle layer P3 and the plurality of organic particles P, and the other surface of the base film 13a can be uncoated or coated with the inorganic particle layer P3. In other examples, both surfaces of the base film 13a are coated with the coating layer 13b including the inorganic particle layer P3 and the organic particles P.

[0225] The inorganic particles and the organic particles P form sufficient and unevenly distributed voids therebetween, which can improve the air permeability of the separator 13 and provide the cylindrical battery cell 7 with better cycle performance and reliability. The organic particles P can support the positive electrode sheet 11 or the negative electrode sheet 12 to increase the gap G and provide space for expansion of the negative electrode sheet 12.

[0226] In some embodiments, the inorganic particles can include one or more of boehmite (γ-AlOOH), aluminum oxide (Al2O3), barium sulfate (BaSO4), magnesium oxide (MgO), magnesium hydroxide (Mg(OH)2), silicon dioxide (SiO2), tin dioxide (SnO2), titanium oxide (TiO2), calcium oxide (CaO), zinc oxide (ZnO), zirconium oxide (ZrO2), yttrium oxide (Y2O3), nickel oxide (NiO), cerium oxide (CeO2), zirconium titanate (SrTiO3), barium titanate (BaTiO3), and magnesium fluoride (MgF2).

[0227] In some embodiments, the volume average particle size Dv50 of the inorganic particles is ≤ 2.5 pm; for example, the particle size of the inorganic particles can be 0.5 pm - 2.5 pm, 1.5 pm - 2.5 pm, 0.3 pm - 0.7 pm, etc.

[0228] In some embodiments, the surface of the base film 13a facing the positive electrode sheet 11 is coated with a coating layer 13b, and / or the surface of the base film 13a facing the negative electrode sheet 12 is coated with a coating layer 13b.

[0229] In some embodiments, the gap G extends along the winding direction V of the electrode assembly 10, and the gap G has a winding start end El and a winding end end E2.

[0230] The gap G is wound into multiple turns along the winding direction V.

[0231] As an example, the positive electrode sheet 11 has a positive electrode winding start end E3 and a positive electrode winding end end E4, and the negative electrode sheet 12 has a negative electrode winding start end E5 and a negative electrode winding end end E6. Along the winding direction V, the negative electrode winding end end E6 exceeds the positive electrode winding end end E4; along the opposite direction of the winding direction V, the negative electrode winding start end E5 exceeds the positive electrode winding start end E3. The negative electrode sheet 12 exceeds the positive electrode sheet 11 at both ends along the winding direction V, and the negative electrode sheet 12 can provide an intercalation space for the active ions released from the positive electrode sheet 11, thereby reducing the risk of ion release. In the radial direction of the cylindrical battery cell, the winding start end El of the gap G corresponds to the positive electrode winding start end E3, and the winding end end E2 of the gap G corresponds to the positive electrode winding end end E4.

[0232] In some embodiments, the radial dimension W of at least part of the gap G is 5 pm - 60 pm.

[0233] As an example, the radial dimension of the gap G can be the dimension of the gap G along the radial direction of the cylindrical battery cell. The radial dimension W of the gap G at different positions can be the same or different.

[0234] Optionally, the radial dimension W of each part of the gap G is 5 pm - 60 pm.

[0235] Optionally, the radial dimension W of the gap G can be 5 pm, 6 pm, 8 pm, 10 pm, 15 pm, 20 pm, 25 pm, 30 pm, 35 pm, 40 pm, 45 pm, 50 pm, 55 pm, 60 pm, or a range formed by any two of the above values.

[0236] As an example, the radial dimension of the gap G can be measured in the following manner:

[0237] Discharge the cylindrical battery cell to the lower limit cut-off voltage (e.g., 2.5 V);

[0238] The CT (Computed Tomography) technology is adopted to obtain an image of a cross section of the electrode assembly by using X-rays, and the cross section is perpendicular to the axial direction of the cylindrical battery cell;

[0239] Based on the image, a distance D1 between the outer surface of the 6th positive electrode sheet and the inner surface of the 10th positive electrode sheet is measured in the radial direction of the electrode assembly;

[0240] The cylindrical battery cell is disassembled, and the thickness t1 of the positive electrode sheet, the thickness t2 of the negative electrode sheet, and the thickness t3 of the separator are measured.

[0241] The 6th positive electrode sheet and the 10th positive electrode sheet are provided with 3 layers of positive electrode sheets, 4 layers of negative electrode sheets, and 8 layers of separators between the outer surface of the 6th positive electrode sheet and the inner surface of the 10th positive electrode sheet, and 8 layers of gaps are formed between the outer surface of the 6th positive electrode sheet and the inner surface of the 10th positive electrode sheet. W = (D1-3×t1-4×t2-8×t3) / 8.

[0242] It is explained that D1 is measured at the position of the outer surface of the 6th positive electrode sheet without the support part and the position of the inner surface of the 10th positive electrode sheet without the support part. t1 is measured at the part of the positive electrode sheet without the support part. The thickness t2 is measured at the part of the negative electrode sheet without the support part. The thickness t3 is measured at the part of the separator without the support part.

[0243] The embodiments of the present application limit the radial size W of the gap G to be greater than or equal to 5 μm, which can provide space for the expansion of the negative electrode sheet 12, reduce the expansion force, improve the cycle performance of the cylindrical battery cell 7, and reduce the risk of deformation and cracking of the shell 20. The embodiments of the present application limit the radial size W of the gap G to be less than or equal to 50 μm, which shortens the ion migration path between the positive electrode sheet 11 and the negative electrode sheet 12, reduces the internal resistance of the cylindrical battery cell 7, reduces heat generation, and reduces the influence of the gap G on the energy density.

[0244] FIG. 9 is a partial cross-sectional schematic view of an electrode assembly of a cylindrical battery cell according to some embodiments of the present application; and FIG. 10 is a schematic view of a separator of an electrode assembly of a cylindrical battery cell according to some embodiments of the present application.

[0245] Referring to FIGS. 9 and 10, in some embodiments, the separator 13 is provided with a plurality of support parts 14 on both sides. The gap G includes a first gap G1 formed between the positive electrode sheet 11 and the separator 13 and a second gap G2 formed between the negative electrode sheet 12 and the separator 13.

[0246] As an example, the first gap G1 has a radial dimension of W1, and the second gap G2 has a radial dimension of W2. The radial dimension W of the gap G = W1 + W2.

[0247] The support portions 14 on both sides of the separator 13 can or can not overlap in the thickness direction of the separator 13.

[0248] By providing multiple support portions 14 on both sides of the separator 13, the gap G can be increased, providing more space for expansion of the negative electrode sheet 12.

[0249] In some embodiments, the separator 13 is provided with a coating 13b on both sides.

[0250] FIG. 11 is a partial cross-sectional view of an electrode assembly of a cylindrical battery cell according to some embodiments of the present application; FIG. 12 is a plan view of a positive electrode sheet of an electrode assembly according to some embodiments of the present application; FIG. 13 is a cross-sectional view of a positive electrode sheet of an electrode assembly according to some embodiments of the present application; and FIG. 14 is a cross-sectional view of a negative electrode sheet of an electrode assembly according to some embodiments of the present application.

[0251] Referring to FIGS. 11 to 14, in some embodiments, the positive electrode sheet 11 is provided with a support portion 14.

[0252] In the embodiments of the present application, the support portion 14 can be provided on one side of the positive electrode sheet 11, or on both sides of the positive electrode sheet 11.

[0253] In some embodiments, the positive electrode sheet 11 includes a positive electrode base portion 111 and multiple positive electrode protrusions 112 protruding from the surface of the positive electrode base portion 111, and the positive electrode sheet 11 is provided with a positive electrode recess portion 113 corresponding to the positive electrode protrusions 112 on the side away from the positive electrode protrusions 112. The support portion 14 of the positive electrode sheet 11 includes the positive electrode protrusions 112.

[0254] As an example, the number of positive electrode recess portions 113 is the same as the number of positive electrode protrusions 112, and each positive electrode recess portion 113 corresponds to one positive electrode protrusion 112.

[0255] The positive electrode protrusions 112 can support the separator 13 and the negative electrode sheet 12, thereby forming the gap G. The positive electrode recess portion 113 can accommodate electrolyte and also provide space for expansion of the negative electrode sheet 12.

[0256] As an example, the positive electrode protrusions 112 and the positive electrode recess portion 113 can be formed by stamping the positive electrode sheet 11.

[0257] In some embodiments, the surface of the positive electrode protrusions 112 can be provided with organic particles.

[0258] In some embodiments, the positive electrode tab is connected to the positive electrode base portion 111.

[0259] In some embodiments, all of the positive protrusions 112 protrude toward the same side of the positive base 111. Correspondingly, the plurality of support portions 14 are arranged on the same side of the positive base 111.

[0260] The embodiments of the present application can simplify the forming process of the positive sheet 11.

[0261] In some embodiments, the positive protrusions 112 are multiple, and a portion of the positive protrusions 112 protrude from the positive base 111 with a higher height, and another portion of the positive protrusions 112 protrude from the positive base 111 with a lower height. The first support portion includes the positive protrusions 112 with the higher height, and the second support portion includes the positive protrusions 112 with the lower height.

[0262] In some embodiments, the plurality of support portions 14 are arranged on the side of the separator 13 facing the positive recess 113, and at least a portion of the plurality of support portions 14 of the separator 13 do not overlap with the positive recess 113 in the radial direction.

[0263] In some embodiments, the positive sheet 11 includes a positive current collector 11a and a positive film layer 11b arranged on the surface of the positive current collector 11a. Exemplarily, the portion of the positive current collector 11a on which the positive film layer 11b is not arranged can be a positive tab.

[0264] In some embodiments, the positive protrusions 112 are formed in the region of the positive sheet 11 on which the positive film layer 11b is arranged.

[0265] In some embodiments, the negative sheet 12 includes a negative current collector 12a and a negative film layer 12b arranged on at least one side of the negative current collector 12a and containing a negative active material.

[0266] Exemplarily, the portion of the negative current collector 12a on which the negative film layer 12b is not arranged can be a negative tab.

[0267] In some embodiments, the negative active material includes a silicon-based material. The introduction of the silicon-based material can improve the capacity of the negative active material and increase the energy density of the cylindrical battery cell 7; the gap G can provide space for the expansion of the silicon-based material, thereby reducing the influence of the silicon-based material on the expansion force.

[0268] Exemplarily, the silicon element can exist in the form of a silicon-based material, for example, the silicon-based material can include at least one of elemental silicon, a silicon oxide compound, a silicon-carbon composite, a silicon-nitrogen composite, and a silicon alloy.

[0269] In some embodiments, the mass content of silicon element in the negative electrode film layer 12b is 2% to 19% of the silicon-based material. Illustratively, the mass content of silicon element in the negative electrode film layer can be 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or a range between any two of the above values.

[0270] The mass content of silicon element in the negative electrode film layer is in the meaning known in the art, which can be detected by using devices and methods known in the art, for example, placing the negative electrode sheet in a solvent (such as water) for soaking, separating the negative electrode active material from the negative electrode current collector, and then performing suction filtration to obtain each substance in the negative electrode film layer, taking the substance as a test sample, and using an inductively coupled plasma-emission spectrometer of ICAP7400 model of Thermo Fisher Scientific Company of the United States to refer to the GB / T30902-2014 standard, so as to obtain the content of silicon element.

[0271] The embodiments of the present application limit the mass content of silicon element in the negative electrode film layer 12b to be greater than or equal to 2%, so as to improve the capacity of the negative electrode sheet and the energy density of the cylindrical battery monomer; the gap G can provide space for the expansion of the negative electrode sheet, so as to reduce the influence of the silicon-based material on the expansion force. The embodiments of the present application limit the mass content of silicon element in the negative electrode film layer 12b to be less than or equal to 19%, so as to limit the expansion amount of the cylindrical battery monomer and improve the cycle performance of the cylindrical battery monomer.

[0272] The embodiments of the present application limit the mass content of silicon element in the negative electrode film layer 12b to be 2% to 19%, so as to balance the expansion and capacity of the negative electrode sheet to a certain extent, and take into account the cycle performance and energy density of the cylindrical battery monomer.

[0273] In some embodiments, the mass content of silicon element in the negative electrode film layer 12b is 6% to 13%.

[0274] In some embodiments, the capacity area density of the negative electrode sheet 12 is greater than or equal to 3.2 mAh / cm 2 .

[0275] The capacity surface density of the negative electrode sheet is in the meaning known in the art, which can be detected by using the devices and methods known in the art, for example, the above-mentioned negative electrode sheet and a lithium metal sheet are assembled into a pair of electrodes, combined with an electrolyte and a separator, and assembled into a CR2430 type button cell in an argon-protected glove box; the obtained button cell is left for 12 h, then discharged at 0.05C constant current to 0.005V at 25°C, left for 10 minutes, discharged at 50 μA constant current to 0.005V again, left for 10 minutes, and discharged at 10 μA constant current to 0.005V; then charged at 0.1C constant current to 2V, and the ratio of the charge capacity to the area of the negative electrode sheet is the capacity surface density. As an example, the electrolyte and the separator can be the electrolyte and the separator of Example 1 described below.

[0276] The surface density of the negative electrode sheet is related to the expansion of the negative electrode sheet. By providing the gap, the influence of the increased surface density of the negative electrode sheet on the expansion force can be reduced, thereby improving the capacity of the negative electrode sheet and the energy density of the cylindrical battery monomer.

[0277] Exemplarily, the capacity surface density of the negative electrode sheet 12 can be 3.2 mAh / cm 2 , 3.3 mAh / cm 2 , 3.33 mAh / cm 2 , 3.5 mAh / cm 2 , 3.8 mAh / cm 2 , 3.9 mAh / cm 2 , 4 mAh / cm 2 , 4.2 mAh / cm 2 , 4.5 mAh / cm 2 , 4.8 mAh / cm 2 , 4.9 mAh / cm 2 , 5 mAh / cm 2 , 5.2 mAh / cm 2 , 5.5 mAh / cm 2 , 5.8 mAh / cm 2 , 6 mAh / cm 2 , 6.2 mAh / cm 2 , 6.5 mAh / cm 2 , 6.8 mAh / cm 2 , 7 mAh / cm 2 , 7.5 mAh / cm 2 , 8 mAh / cm 2 , 8.5 mAh / cm 2 , 9 mAh / cm 2 , 9.5 mAh / cm 2 , 10 mAh / cm 2 , 10.5 mAh / cm2 11 mAh / cm 2 11.5 mAh / cm 2 or a range consisting of any two of the aforementioned values.

[0278] In some embodiments, the capacity surface density of the negative electrode sheet 12 is 3.3 mAh / cm 2 to 11.5 mAh / cm 2 The embodiments of the present application can balance the capacity and expansion of the negative electrode sheet to some extent, and take into account the energy density and cycle performance of the cylindrical battery cell.

[0279] In some embodiments, the capacity surface density of the negative electrode sheet 12 is 3.96 mAh / cm 2 to 7.56 mAh / cm 2 , which can further take into account the energy density and cycle performance of the cylindrical battery cell.

[0280] In some embodiments, the negative electrode sheet 12 is provided with a plurality of support portions 14.

[0281] In the embodiments of the present application, the negative electrode sheet 12 can be provided with a plurality of support portions 14 on one side, or a plurality of support portions 14 on both sides.

[0282] In some embodiments, the negative electrode sheet 12 includes a negative electrode base 121 and a plurality of negative electrode protrusions 122 protruding from the surface of the negative electrode base 121, and the negative electrode sheet 12 is provided with a negative electrode recess 123 corresponding to the negative electrode protrusion 122 on the side away from the negative electrode protrusion 122. The support portion 14 of the negative electrode sheet 12 includes the negative electrode protrusion 122.

[0283] As an example, the negative electrode recess 123 and the negative electrode protrusion 122 are the same in number and are one-to-one corresponding.

[0284] The negative electrode protrusion 122 can support the separator 13 and the positive electrode sheet 11, thereby forming a gap G. The negative electrode recess 123 can accommodate the electrolyte, and can also provide space for the expansion of the negative electrode sheet 12.

[0285] As an example, the negative electrode protrusion 122 and the negative electrode recess 123 can be formed by stamping the negative electrode sheet 12.

[0286] In some embodiments, the surface of the negative electrode protrusion 122 can be provided with organic particles.

[0287] In some embodiments, the negative electrode tab is connected to the negative electrode base 121.

[0288] In some embodiments, the negative electrode protrusion 122 is a plurality.

[0289] In some embodiments, all of the negative protrusions 122 protrude toward the same side of the negative base 121. Correspondingly, the plurality of support portions 14 are arranged on the same side of the negative base 121.

[0290] The embodiments of the present application can simplify the forming process of the negative sheet 12.

[0291] In some embodiments, the negative protrusions 122 are a plurality of negative protrusions, a portion of the negative protrusions 122 protrude from the negative base 121 at a higher height, and another portion of the negative protrusions 122 protrude from the negative base 121 at a lower height. The first support portion includes the negative protrusions 122 protruding at the higher height, and the second support portion includes the negative protrusions 122 protruding at the lower height.

[0292] In some embodiments, the plurality of support portions 14 are arranged on the side of the separator 13 facing the negative recess 123, and at least a portion of the plurality of support portions 14 of the separator 13 do not overlap the negative recess 123 in the radial direction.

[0293] In some embodiments, the negative protrusions 122 are formed in the region of the negative sheet 12 where the negative film layer 12b is arranged.

[0294] In some embodiments, the gap G is formed between the negative film layer 12b and the positive film layer 11b.

[0295] In some embodiments, the positive sheet 11 is provided with a plurality of support portions 14 on the side facing the separator 13, the separator 13 is provided with a plurality of support portions 14 on the side facing the positive sheet 11, and the plurality of support portions 14 of the positive sheet 11 facing the separator 13 and the plurality of support portions 14 of the separator 13 facing the positive sheet 11 are arranged at least partially opposite to each other.

[0296] Optionally, the negative sheet 12 is not provided with support portions.

[0297] As an example, the positive sheet 11 is provided with separators 13 on both sides, the separator 13 located on the inner side of the positive sheet 11 is referred to as an inner separator, and the separator 13 located on the outer side of the positive sheet 11 is referred to as an outer separator.

[0298] In some examples, the positive sheet 11 is provided with a plurality of support portions 14 on the side facing the inner separator, the inner separator is provided with a plurality of support portions 14 on the side facing the positive sheet 11, and the plurality of support portions 14 of the positive sheet 11 and the plurality of support portions 14 of the inner separator are arranged at least partially opposite to each other. For example, the plurality of positive protrusions 112 of the positive sheet 11 and the plurality of organic particles of the inner separator are arranged at least partially opposite to each other.

[0299] In some examples, the positive plate 11 is provided with a plurality of support portions 14 on one side facing the separator 13, and the separator 13 is provided with a plurality of support portions 14 on one side facing the positive plate 11, and the plurality of support portions 14 of the positive plate 11 facing the separator 13 and the plurality of support portions 14 of the separator 13 facing the positive plate 11 are at least partially opposite to each other.

[0300] In some examples, the positive plate 11 is provided with a plurality of support portions 14 on one side facing the separator 13, and the separator 13 is provided with a plurality of support portions 14 on one side facing the positive plate 11, and the plurality of support portions 14 of the positive plate 11 facing the separator 13 and the plurality of support portions 14 of the separator 13 facing the positive plate 11 are at least partially opposite to each other.

[0301] By arranging the plurality of support portions 14 of the positive plate 11 and the plurality of support portions 14 of the separator 13 to face each other, the plurality of support portions 14 of the positive plate 11 and the plurality of support portions 14 of the separator 13 can at least partially abut each other, so as to increase the gap G and provide more space for the expansion of the negative plate 12.

[0302] As an example, the embodiments of the present application can reduce the depth of the positive recess 113 and the particle size of the organic particle, reduce the damage of the positive plate 11 during stamping, and improve the cycle life of the cylindrical battery cell 7.

[0303] In some examples, the negative plate 12 is provided with a plurality of support portions 14 on one side facing the separator 13, and the separator 13 is provided with a plurality of support portions 14 on one side facing the negative plate 12, and the plurality of support portions 14 of the negative plate 12 facing the separator 13 and the plurality of support portions 14 of the separator 13 facing the negative plate 12 are at least partially opposite to each other.

[0304] Optionally, the positive plate 11 is not provided with a support portion.

[0305] As an example, the negative plate 12 is provided with a separator 13 on both sides, and the separator 13 located on the inner side of the negative plate 12 is referred to as an inner separator, and the separator 13 located on the outer side of the negative plate 12 is referred to as an outer separator.

[0306] In some examples, the negative plate 12 is provided with a plurality of support portions 14 on one side facing the inner separator, and the inner separator is provided with a plurality of support portions 14 on one side facing the negative plate 12, and the plurality of support portions 14 of the negative plate 12 and the plurality of support portions 14 of the inner separator are at least partially opposite to each other. For example, the plurality of negative protrusions 122 of the negative plate 12 and the plurality of organic particles of the inner separator are at least partially opposite to each other.

[0307] In some examples, the negative electrode sheet 12 is provided with a plurality of support portions 14 on a side facing the outer separator, and the outer separator is provided with a plurality of support portions 14 on a side facing the negative electrode sheet 12. The plurality of support portions 14 of the negative electrode sheet 12 and the plurality of support portions 14 of the outer separator are at least partially arranged opposite to each other. For example, the plurality of negative electrode protrusions 122 of the negative electrode sheet 12 and the plurality of organic particles of the outer separator are at least partially arranged opposite to each other.

[0308] In some examples, the negative electrode sheet 12 is provided with a plurality of support portions 14 on a side facing the outer separator, and the outer separator is provided with a plurality of support portions 14 on a side facing the negative electrode sheet 12. The plurality of support portions 14 of the negative electrode sheet 12 and the plurality of support portions 14 of the outer separator are at least partially arranged opposite to each other. For example, the plurality of negative electrode protrusions 122 of the negative electrode sheet 12 and the plurality of organic particles of the outer separator are at least partially arranged opposite to each other.

[0309] In some examples, the negative electrode sheet 12 is provided with a plurality of support portions 14 on a side facing the outer separator, and the outer separator is provided with a plurality of support portions 14 on a side facing the negative electrode sheet 12. The plurality of support portions 14 of the negative electrode sheet 12 and the plurality of support portions 14 of the outer separator are at least partially arranged opposite to each other. For example, the plurality of negative electrode protrusions 122 of the negative electrode sheet 12 and the plurality of organic particles of the outer separator are at least partially arranged opposite to each other.

[0310] In some examples, the negative electrode sheet 12 is provided with a plurality of support portions 14 on a side facing the outer separator, and the outer separator is provided with a plurality of support portions 14 on a side facing the negative electrode sheet 12. The plurality of support portions 14 of the negative electrode sheet 12 and the plurality of support portions 14 of the outer separator are at least partially arranged opposite to each other. For example, the plurality of negative electrode protrusions 122 of the negative electrode sheet 12 and the plurality of organic particles of the outer separator are at least partially arranged opposite to each other.

[0311] In some examples, the negative electrode sheet 12 is provided with a plurality of support portions 14 on a side facing the outer separator, and the outer separator is provided with a plurality of support portions 14 on a side facing the negative electrode sheet 12. The plurality of support portions 14 of the negative electrode sheet 12 and the plurality of support portions 14 of the outer separator are at least partially arranged opposite to each other. For example, the plurality of negative electrode protrusions 122 of the negative electrode sheet 12 and the plurality of organic particles of the outer separator are at least partially arranged opposite to each other.

[0312] In some examples, the negative electrode sheet 12 is provided with a plurality of support portions 14 on a side facing the outer separator, and the outer separator is provided with a plurality of support portions 14 on a side facing the negative electrode sheet 12. The plurality of support portions 14 of the negative electrode sheet 12 and the plurality of support portions 14 of the outer separator are at least partially arranged opposite to each other. For example, the plurality of negative electrode protrusions 122 of the negative electrode sheet 12 and the plurality of organic particles of the outer separator are at least partially arranged opposite to each other.

[0313] In some examples, the negative electrode sheet 12 is provided with a plurality of support portions 14 on a side facing the outer separator, and the outer separator is provided with a plurality of support portions 14 on a side facing the negative electrode sheet 12. The plurality of support portions 14 of the negative electrode sheet 12 and the plurality of support portions 14 of the outer separator are at least partially arranged opposite to each other. For example, the plurality of negative electrode protrusions 122 of the negative electrode sheet 12 and the plurality of organic particles of the outer separator are at least partially arranged opposite to each other.

[0314] In some examples, the negative electrode sheet 12 is provided with a plurality of support portions 14 on a side facing the outer separator, and the outer separator is provided with a plurality of support portions 14 on a side facing the negative electrode sheet 12. The plurality of support portions 14 of the negative electrode sheet 12 and the plurality of support portions 14 of the outer separator are at least partially arranged opposite to each other. For example, the plurality of negative electrode protrusions 122 of the negative electrode sheet 12 and the plurality of organic particles of the outer separator are at least partially arranged opposite to each other.

[0315] In some examples, the positive electrode sheet 11 is provided with a plurality of support portions 14 on both the inner side and the outer side, and the negative electrode sheet 12 is provided with a plurality of support portions 14 on both the inner side and the outer side; the plurality of support portions 14 on the outer side of the positive electrode sheet 11 are arranged to face the plurality of support portions 14 on the inner side of the negative electrode sheet 12 and overlap in the radial direction, and the plurality of support portions 14 on the inner side of the positive electrode sheet 11 are arranged to face the plurality of support portions 14 on the outer side of the negative electrode sheet 12 and overlap in the radial direction.

[0316] By arranging the plurality of support portions 14 of the negative electrode sheet 12 to face the plurality of support portions 14 of the positive electrode sheet 11, the plurality of support portions 14 of the negative electrode sheet 12 and the plurality of support portions 14 of the positive electrode sheet 11 can support each other to increase the gap G and provide more space for the expansion of the negative electrode sheet 12.

[0317] As an example, the embodiments of the present application can reduce the depth of the negative electrode recess 123 and the depth of the positive electrode recess 113, reduce the damage of the positive electrode sheet 11 and the negative electrode sheet 12 during stamping, and improve the cycle life of the cylindrical battery cell 7.

[0318] In some embodiments, the positive electrode sheet 11, the negative electrode sheet 12, and the separator 13 are each provided with a plurality of support portions 14.

[0319] Optionally, the separator 13 is provided with a plurality of support portions 14 on both sides.

[0320] Optionally, the positive electrode sheet 11 is provided with a plurality of support portions 14 on the outer side, and the negative electrode sheet 12 is provided with a plurality of support portions 14 on the inner side; alternatively, the positive electrode sheet 11 is provided with a plurality of support portions 14 on the inner side, and the negative electrode sheet 12 is provided with a plurality of support portions 14 on the outer side.

[0321] FIG. 15 is a cross-sectional view of a positive electrode sheet according to some embodiments of the present application.

[0322] Referring to FIG. 15, in some embodiments, the positive electrode sheet 11 includes a positive electrode base 111 and a plurality of support portions 14, and the support portions 14 include organic particles provided on the positive electrode base 111.

[0323] The organic particles P can protrude from the positive electrode base 111 as a whole. Alternatively, part of the organic particles is embedded in the positive electrode base 111, and the other part protrudes from the positive electrode base 111.

[0324] The organic particles P of the positive electrode sheet 11 can support the negative electrode sheet 12 to increase the gap G and provide space for the expansion of the negative electrode sheet 12.

[0325] In some embodiments, the positive electrode base 111 includes a positive electrode current collector 11a, a positive electrode film layer 11b disposed on a surface of the positive electrode current collector 11a, and an inorganic particle layer P3 coated on a surface of the positive electrode film layer 11b facing away from the positive electrode current collector. The organic particles P at least partially protrude from the inorganic particle layer P3.

[0326] The positive electrode film layer 11b includes a positive electrode active material, and the inorganic particle layer P3 includes a plurality of inorganic particles.

[0327] In some embodiments, a portion of the organic particles P is embedded in the inorganic particle layer P3, and a portion of the organic particles P protrudes from the inorganic particle layer P3.

[0328] In some embodiments, the positive electrode tab 11 includes a positive electrode particle coating layer 11c disposed on a surface of the positive electrode film layer 11b. The positive electrode particle coating layer 11c includes the inorganic particle layer P3 and the plurality of organic particles P.

[0329] In some examples, the inorganic particles can be coated on the positive electrode film layer 11b first to form the inorganic particle layer P3, and then the plurality of organic particles can be coated on the inorganic particle layer P3. In other examples, the inorganic particles and the organic particles can be mixed together and then coated on the positive electrode film layer 11b.

[0330] As an example, the positive electrode particle coating layer 11c does not include a positive electrode active material.

[0331] In some embodiments, the plurality of organic particles P includes first organic particles P1 and second organic particles P2, and a number average particle size of the first organic particles P1 is greater than a number average particle size of the second organic particles P2.

[0332] FIG. 16 is a cross-sectional view of a negative electrode tab according to some embodiments of the present application.

[0333] Referring to FIG. 16, in some embodiments, the negative electrode tab 12 includes a negative electrode base 121 and a plurality of support portions 14 including organic particles P disposed on the negative electrode base 121.

[0334] The organic particles P can protrude from the negative electrode base 121 as a whole. Alternatively, a portion of the organic particles is embedded in the negative electrode base 121, and another portion of the organic particles protrudes from the negative electrode base 121.

[0335] The organic particles P of the negative electrode tab 12 can support the positive electrode tab 11 to increase the gap G and provide space for expansion of the negative electrode tab 12.

[0336] In some embodiments, the negative electrode base 121 includes a negative electrode current collector 12a, a negative electrode film layer 12b disposed on a surface of the negative electrode current collector 12a, and an inorganic particle layer P3 coated on a surface of the negative electrode film layer 12b facing away from the negative electrode current collector 12a. The organic particles P at least partially protrude from the inorganic particle layer P3.

[0337] The negative electrode film layer 12b includes a negative electrode active material, and the inorganic particle layer P3 includes a plurality of inorganic particles.

[0338] In some embodiments, a portion of the organic particles P is embedded in the inorganic particle layer P3, and a portion of the organic particles P protrudes from the inorganic particle layer P3.

[0339] In some embodiments, the negative electrode sheet 12 includes a negative electrode particle coating layer 12c disposed on a surface of the negative electrode film layer 12b. The negative electrode particle coating layer 12c includes the inorganic particle layer P3 and a plurality of organic particles P.

[0340] In some examples, the inorganic particle layer P3 can be formed by coating inorganic particles on the negative electrode film layer 12b first, and then coating the plurality of organic particles on the inorganic particle layer P3. In other examples, the inorganic particles and the organic particles can be mixed together and then coated on the negative electrode film layer 12b.

[0341] As an example, the negative electrode particle coating layer 12c does not include a negative electrode active material.

[0342] In some embodiments, the plurality of organic particles P includes first organic particles P1 and second organic particles P2, and a number average particle size of the first organic particles P1 is greater than a number average particle size of the second organic particles P2.

[0343] FIG. 17 is a partial cross-sectional view of an electrode assembly of a cylindrical battery cell according to some embodiments of the present application. FIG. 17 shows a circle of positive electrode sheets, a circle of negative electrode sheets, and a circle of separators.

[0344] Referring to FIGS. 6 and 17, in some embodiments, a radial dimension of a portion of the gap G near the winding start end El is greater than or equal to a radial dimension of a portion of the gap G near the winding end E2.

[0345] In embodiments of the present application, the radial dimensions of different portions of the gap G along the winding direction V are compared in the same cross-section perpendicular to the axial direction Z.

[0346] The “portion of the gap G near the winding start end El” does not require extending from the winding start end El. As an example, the “portion of the gap G near the winding start end El” can extend from a position 1-5 turns away from the winding start end El in the winding direction V.

[0347] The portion of the gap G near the winding end E2 does not require extending to the winding end E2 along the winding direction V. As an example, the tail end of the portion of the gap G near the winding end E2 along the winding direction V can be 1-5 windings away from the winding end E2.

[0348] In embodiments of the application, the portion of the gap G near the winding start E1 has a larger radial dimension to provide more expansion space for the negative electrode sheet 12 in the middle of the electrode assembly 10, reduce the risk of the middle of the electrode assembly 10 collapsing due to expansion, and improve the cycle performance of the cylindrical battery cell 7.

[0349] In some embodiments, the gap G extends along the winding direction V and is wound into n windings, each winding being defined as a winding turn, and n≥20. The average of the radial dimensions of the 5th-9th winding turns is greater than the average of the radial dimensions of the n-9th to n-5th winding turns.

[0350] It is explained herein that n does not require being an integer, in other words, the 1st to n-1th winding turns are each an integer turn; the portion from the end of the n-1th winding turn to the winding end E2 can or can not be an integer turn, for example, 1 / 4 turn, 1 / 2 turn, or 3 / 4 turn.

[0351] In embodiments of the application, the portion of the gap G near the winding start E1 has a larger radial dimension to provide more expansion space for the negative electrode sheet 12 in the middle of the electrode assembly 10, reduce the risk of the middle of the electrode assembly 10 collapsing due to expansion, and improve the cycle performance of the cylindrical battery cell 7.

[0352] In some embodiments, the radial dimension of at least part of the gap G gradually decreases along the winding direction V.

[0353] The gradual change in the radial dimension of the gap G reduces the abrupt change in the radial dimension of the gap G, reduces the stress concentration of the negative electrode sheet 12, and improves the cycle performance of the cylindrical battery cell 7.

[0354] FIG. 18 is a partial cross-sectional view of an electrode assembly of a cylindrical battery cell according to some embodiments of the application.

[0355] Referring to FIG. 18, in some embodiments, the gap G includes a middle region C1 and two end regions C2 arranged along the axial direction Z of the cylindrical battery cell, the middle region C1 being located between the two end regions C2, and the radial dimension of the middle region C1 being smaller than the radial dimension of the end regions C2.

[0356] In embodiments of the application, the radial dimension of the middle region C1 and the radial dimension of the end regions C2 are compared in a cross-section of one winding turn parallel to the axial direction Z.

[0357] The gap G has a first end E7 and a second end E8 oppositely arranged along the axial direction Z; a dimension of the gap G along the axial direction Z is defined as L, i.e., a distance between the first end E7 and the second end E8 along the axial direction Z is L.

[0358] The end region C2 is a region having a dimension along the axial direction Z. One end region C2 is a region extending to a length L1 from the first end E7 toward the second end E8, and the other end region C2 is a region extending to the length L1 from the second end E8 toward the first end E7. The middle region C1 includes a region extending to a length L2 from the middle section S toward the first end E7 and a region extending to the length L2 from the middle section S toward the second end E8. The middle section S is a section perpendicular to the axial direction Z; along the axial direction Z, a distance between the middle section S and the first end E7 is equal to a distance between the middle section S and the second end E8.

[0359] Exemplarily, L1 / L is 0.1-0.3, and can be 0.2. Exemplarily, L2 / L is 0.03-0.2, and can be 0.1.

[0360] Exemplarily, L1 can be 20 mm, and L2 can be 5 mm.

[0361] Exemplarily, a minimum radial dimension of the end region C2 is greater than a maximum radial dimension of the middle region C1.

[0362] In the embodiments of the present application, the end region C2 has a larger radial dimension, so as to facilitate the electrolyte to enter the gap G, improve the wettability of the electrolyte to the electrode sheet, and improve the cycle performance of the cylindrical battery cell 7.

[0363] In some embodiments, the radial dimension of the middle region is 5 μm-60 μm, and can be 10 μm-30 μm.

[0364] In some embodiments, the gap G further includes a transition region C3 connecting the middle region C1 and the end region C2.

[0365] In some embodiments, in a direction from the end region C2 to the middle region C1, the radial dimension of the gap G gradually decreases, so as to reduce the sudden change of the radial dimension of the gap G, reduce the stress concentration of the negative electrode sheet 12, and improve the cycle performance of the cylindrical battery cell 7.

[0366] FIG. 19 is a sectional view of the battery cell shown in FIG. 4; and FIG. 20 is an enlarged view of the circle frame in FIG. 19.

[0367] Referring to FIGS. 4, 5, 19 and 20, in some embodiments, one of the positive electrode sheet 11 and the negative electrode sheet 12 includes the first tab 10a, and the other includes the second tab 10b. In other words, one of the first tab 10a and the second tab 10b is a positive tab, and the other is a negative tab.

[0368] The first tab 10a and the second tab 10b can be located at the same end of the electrode assembly 10 along the axial direction Z, or can be located at two ends of the electrode assembly 10 along the axial direction Z, respectively.

[0369] In some embodiments, the portion of the positive electrode sheet 11 having the positive electrode film layer, the portion of the negative electrode sheet 12 having the negative electrode film layer, and the separator 13 constitute an electrode body 10c of the electrode assembly 10. The first tab 10a and the second tab 10b are drawn out from one end of the electrode body 10c, or are drawn out from two ends of the electrode body 10c, respectively.

[0370] In some embodiments, the first tab 10a is wound in multiple turns along the winding direction V. Optionally, the end portion of the first tab 10a is bent by a kneading or smoothing process, and forms a multi-layer structure stacked in the axial direction Z.

[0371] In some embodiments, the second tab 10b is wound in multiple turns along the winding direction V. Optionally, the end portion of the second tab 10b is bent by a kneading or smoothing process, and forms a multi-layer structure stacked in the axial direction Z.

[0372] In some embodiments, the cylindrical battery cell 7 includes a first electrode lead-out portion 7a and a second electrode lead-out portion 7b, the first electrode lead-out portion 7a being electrically connected to the first tab 10a, and the second electrode lead-out portion 7b being electrically connected to the second tab 10b. The first electrode lead-out portion 7a and the second electrode lead-out portion 7b are insulated from each other.

[0373] The first electrode lead-out portion 7a and the second electrode lead-out portion 7b are used to be connected with an external circuit to achieve charging or discharging of the cylindrical battery cell 7. Exemplarily, when a plurality of cylindrical battery cells 7 are assembled into a group, the first electrode lead-out portion 7a and the second electrode lead-out portion 7b are used to be connected with a current lead member.

[0374] The first electrode lead-out portion 7a can be an electrode terminal 30 provided on the outer shell 20. The electrode terminal 30 is independently formed with the outer shell 20, and is assembled together in the production process of the cylindrical battery cell 7. Exemplarily, the electrode terminal 30 is insulatively provided on the end cover 22 or the shell body 21.

[0375] Alternatively, the first electrode lead-out portion 7a can also be a part of the outer shell 20. For example, the first electrode lead-out portion 7a can be the end cover 22 of the outer shell 20, or the first electrode lead-out portion 7a is an end wall 211 of the shell body 21 opposite to the end cover 22.

[0376] The second electrode lead-out part 7b can be an electrode terminal 30 provided on the shell 20. Alternatively, the second electrode lead-out part 7b can be a part of the shell 20. For example, the second electrode lead-out part 7b can be an end cover 22 of the shell 20, or the second electrode lead-out part 7b can be an end wall 211 of the shell 21 opposite to the end cover 22.

[0377] In some embodiments, the first electrode lead-out part 7a and the second electrode lead-out part 7b are located on the same side of the electrode assembly 10 in the axial direction Z of the cylindrical battery cell.

[0378] When a plurality of cylindrical battery cells 7 are assembled into a group, the first electrode lead-out part 7a and the second electrode lead-out part 7b of the plurality of cylindrical battery cells 7 can be arranged on the same side, facilitating the connection of the current collecting member to the first electrode lead-out part 7a and the second electrode lead-out part 7b and simplifying the battery structure.

[0379] In some embodiments, the shell 20 includes a shell body 21 and an end cover 22, the shell body 21 includes an integrally formed side wall 212 and an end wall 211, the end wall 211 and the end cover 22 are opposite in the axial direction Z of the cylindrical battery cell, and the end cover 22 is sealingly connected to the side wall 212.

[0380] The end cover 22 can be insulated from the side wall 212 or electrically connected.

[0381] The shell body 21 has an opening at an end away from the end wall 211, and the end cover 22 covers the opening of the shell body 21.

[0382] In some embodiments, one of the positive electrode tab 11 and the negative electrode tab 12 includes the first electrode tab 10a, and the other includes the second electrode tab 10b. The cylindrical battery cell 7 further includes an electrode terminal 30 insulated from the end wall 211, one of the first electrode tab 10a and the second electrode tab 10b is electrically connected to the electrode terminal 30, and the other is electrically connected to the end wall 211.

[0383] For example, the first electrode tab 10a is electrically connected to the electrode terminal 30, and the second electrode tab 10b is electrically connected to the end wall 211. The second electrode tab 10b can be directly connected to the end wall 211 or indirectly connected to the end wall 211 through the end cover 22, the side wall 212 or other components.

[0384] One of the electrode terminal 30 and the end wall 211 serves as the first electrode lead-out part 7a, and the other serves as the second electrode lead-out part 7b.

[0385] The electrode terminal 30 and the end wall 211 can serve as two exposed electrodes of the cylindrical battery cell 7, and the electrode terminal 30 and the end wall 211 are located on the same side, facilitating the assembly of a plurality of cylindrical battery cells 7 into a group and simplifying the battery structure.

[0386] In some embodiments, the cylindrical battery cell 7 further comprises a first current collecting member 40 located on the side of the first tab 10a facing the end wall 211 and connected to the first tab 10a. The electrode terminal 30 abuts against and is connected to the surface of the first current collecting member 40 facing the end wall 211.

[0387] The first current collecting member 40 can serve as an adapter to achieve electrical connection between the first tab 10a and the electrode terminal 30.

[0388] In some embodiments, the first current collecting member 40 is annular.

[0389] In some embodiments, the side of the electrode terminal 30 facing the first current collecting member 40 is provided with a terminal recess 31, and the bottom wall of the terminal recess 31 is welded to the first current collecting member 40.

[0390] By providing the terminal recess 31, the thickness of the bottom wall of the terminal recess 31 can be reduced, the power required for welding the electrode terminal 30 and the first current collecting member 40 from the outside can be reduced, the risk of particles generated by welding falling into the housing 20 can be reduced, and the reliability of the cylindrical battery cell 7 can be improved.

[0391] Providing the terminal recess 31 on the inner side of the electrode terminal 30 can also increase the internal space of the cylindrical battery cell 7.

[0392] In some embodiments, the side of the electrode terminal 30 facing away from the first current collecting member 40 is provided with a terminal recess 31.

[0393] In some embodiments, the side of the electrode terminal 30 facing the first current collecting member 40 is provided with one terminal recess 31, and the side of the electrode terminal 30 facing away from the first current collecting member 40 is provided with another terminal recess 31; the bottom surfaces of the two terminal recesses 31 are welded to the first current collecting member 40.

[0394] In some embodiments, the bottom wall of the terminal recess 31 is provided with a through hole 32, which can be used for injecting electrolyte.

[0395] In some embodiments, the cylindrical battery cell 7 further comprises a cover plate 50 connected to the electrode terminal 30 and used to separate the through hole 32 from the external space of the cylindrical battery cell 7.

[0396] In some embodiments, at least part of the cover plate 50 is accommodated in the terminal recess 31. In some embodiments, the first electrode lead-out part comprises the cover plate 50 and the electrode terminal 30.

[0397] In some embodiments, the electrode terminal 30 is riveted to the end wall 211.

[0398] In some embodiments, the first tab 10a is located at one end of the electrode assembly 10 facing the end wall 211, and the second tab 10b is located at one end of the electrode assembly 10 facing the end cover 22. The cylindrical battery cell 7 further comprises a second current collecting member 60 connected to the second tab 10b; the second current collecting member 60 is connected to at least one of the end cover 22 and the side wall 212.

[0399] In some examples, the second current collecting member 60 is connected to the end cover 22, and the end cover 22 is electrically connected to the side wall 212. The second tab 10b is electrically connected to the end wall 211 through the second current collecting member 60, the end cover 22, and the side wall 212.

[0400] In other examples, the second current collecting member 60 is connected to the side wall 212. The second tab 10b is electrically connected to the end wall 211 through the second current collecting member 60 and the side wall 212. Optionally, the end cover 22 is provided in an insulating manner with the side wall 212.

[0401] In some embodiments, the shell 20 comprises a side wall 212 provided around the electrode assembly 10, and the thickness of the side wall 212 is 0.3mm to 1.5mm. The material of the side wall 212 comprises steel.

[0402] For example, the thickness of the side wall 212 is 0.3mm, 0.31mm, 0.32mm, 0.33mm, 0.35mm, 0.38mm, 0.40mm, 0.42mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, 0.75mm, 0.8mm, 0.85mm, 0.9mm, 0.95mm, 1mm, 1.05mm, 1.1mm, 1.15mm, 1.2mm, 1.3mm, 1.35mm, 1.4mm, 1.45mm, or 1.5mm.

[0403] In the embodiments of the present application, the thickness of the side wall 212 is in the meaning known in the art, and can be detected by using the devices and methods known in the art, for example, can be measured by using a screw micrometer or a vernier caliper.

[0404] For example, the material of the side wall 212 comprises stainless steel.

[0405] By providing the gap G, the present application can reduce the expansion force of the electrode assembly 10 on the side wall 212, and therefore, the steel side wall 212 can have a thickness less than or equal to 1.5mm, thereby improving the energy density of the cylindrical battery cell 7. The thickness of the steel side wall 212 is greater than or equal to 0.3mm, so as to reduce the risk of deformation and rupture of the side wall 212 under the expansion force of the electrode assembly 10, and improve the reliability of the cylindrical battery cell 7.

[0406] The mechanical strength of the side wall 212 is relatively high and is not easy to deform, which is suitable for use with the silicon-containing negative electrode sheet 12 and is beneficial to improving the energy density of the battery monomer and making the battery monomer have excellent use reliability.

[0407] In some embodiments, the thickness of the side wall 212 is 0.3 mm to 1.2 mm.

[0408] In some embodiments, the thickness of the side wall 212 is 0.3 mm to 0.9 mm, and optionally 0.3 mm to 0.6 mm.

[0409] In some embodiments, the capacity area density of the negative electrode sheet is greater than or equal to 3.2 mAh / cm 2 The base material of the side wall 212 includes steel, and the thickness of the side wall 212 is 0.3 mm to 0.9 mm. The negative electrode sheet with the above capacity area density and the side wall 212 with the above thickness are used together, which is beneficial to improving the energy density of the battery monomer 7, making the battery monomer 7 have excellent use reliability, and improving the cycle performance.

[0410] In some embodiments, the material of the end wall 211 is the same as that of the side wall 212.

[0411] In some embodiments, the material of the end wall 211 is the same as that of the side wall 212.

[0412] In some embodiments, the material of the end wall 211 is the same as that of the side wall 212.

[0413] Optionally, the height of the shell 20 is 1.3 times, 1.4 times, 1.5 times, 1.6 times, 1.7 times, 1.8 times, 1.9 times, 2.0 times, 2.1 times, 2.2 times, 2.3 times, 2.4 times, 2.5 times, 2.6 times, 2.7 times, 2.8 times, 2.9 times, 3.0 times, 3.1 times, 3.2 times, 3.3 times, 3.4 times, 3.5 times, 3.6 times, 3.7 times, 3.8 times, 3.9 times, or 4.0 times of the diameter of the shell 20.

[0414] When the shell 20 meets the above size requirements, the structural stability of the shell 20 is relatively high, which can improve the use reliability of the cylindrical battery monomer 7.

[0415] In some embodiments, the height of the shell 20 is 1.5 times to 2.5 times of the diameter of the shell 20.

[0416] In some embodiments, the height of the housing 20 is 50mm to 150mm. For example, the height of the housing 20 is 50mm, 55mm, 60mm, 65mm, 70mm, 75mm, 80mm, 85mm, 90mm, 95mm, 100mm, 105mm, 110mm, 115mm, 120mm, 125mm, 130mm, 135mm, 140mm, 145mm or 150mm.

[0417] Optionally, the height of the housing 20 is 60mm to 100mm.

[0418] In some embodiments, the diameter of the housing 20 is 45mm to 80mm. For example, the diameter of the housing 20 is 45mm, 50mm, 55mm, 60mm, 65mm, 70mm, 75mm or 80mm.

[0419] Optionally, the diameter of the housing 20 is 45mm to 60mm.

[0420] Figure 21 is a schematic view of a partial cross-section of a battery cell according to some embodiments of the application.

[0421] Referring to Figure 21, in some embodiments, the first tab 10a and the second tab 10b are both located at one end of the electrode assembly 10 facing the end wall 211. The first tab 10a and the second tab 10b can share space in the axial direction Z, thereby improving space utilization and increasing energy density.

[0422] In some embodiments, the cylindrical battery cell 7 includes two electrode terminals 30 disposed at the end wall 211, and the first tab 10a and the second tab 10b are electrically connected to the two electrode terminals 30 respectively. The two electrode terminals 30 are the first electrode lead-out portion 7a and the second electrode lead-out portion 7b respectively.

[0423] Optionally, the cylindrical battery cell 7 includes a first current collecting member 40 and a second current collecting member 60, the first current collecting member 40 connects the first tab 10a and one of the electrode terminals 30, and the second current collecting member 60 connects the second tab 10b and the other electrode terminal 30.

[0424] In other embodiments, the cylindrical battery cell includes one electrode terminal disposed at the end wall, the first tab is electrically connected to the electrode terminal, and the second tab is electrically connected to the end wall.

[0425] In some embodiments, the projection of the first tab 10a along the axial direction Z is a sector.

[0426] In some embodiments, the projection of the second tab 10b along the axial direction Z is a sector.

[0427] According to some embodiments of the present application, the present application also provides a battery comprising a plurality of the cylindrical battery cell 7 of any one of the above embodiments.

[0428] According to some embodiments of the present application, the present application also provides an electric device comprising the cylindrical battery cell 7 of any one of the above embodiments, the cylindrical battery cell 7 being configured to provide electric energy for the electric device. The electric device can be any of the devices or systems mentioned above.

[0429] Referring to FIGS. 4-9, the present application provides a cylindrical battery cell 7 comprising a housing 20, an electrode assembly 10, an electrode terminal 30, a first current collecting member 40, and a second current collecting member 60.

[0430] The housing 20 comprises a shell 21 and an end cap 22, the shell 21 comprising an integrally formed side wall 212 and an end wall 211, the end wall 211 and the end cap 22 being opposite along an axial direction Z of the cylindrical battery cell, and the end cap 22 being welded to the side wall 212.

[0431] The electrode terminal 30 is insulatively disposed on the end wall 211.

[0432] At least a portion of the electrode assembly 10 is accommodated in the housing 20. The electrode assembly 10 comprises a positive electrode sheet 11, a negative electrode sheet 12, and a separator 13, the positive electrode sheet 11, the negative electrode sheet 12, and the separator 13 being wound together, and the separator 13 separating the positive electrode sheet 11 and the negative electrode sheet 12.

[0433] The positive electrode sheet 11 has a first tab 10a at an end thereof facing the end wall 211, the first current collecting member 40 connecting the electrode terminal 30 and the first tab 10a, and the negative electrode sheet 12 has a second tab 10b at an end thereof facing the end cap 22, the second current collecting member 60 connecting the first tab 10a and the end cap 22.

[0434] The separator 13 comprises a base film 13a and a coating layer 13b disposed on at least one surface of the base film 13a. The coating layer 13b comprises an inorganic particle layer P3 and a plurality of organic particles P, the organic particles P at least partially protruding from the inorganic particle layer P3, and the organic particles P being configured to support the positive electrode sheet 11 or the negative electrode sheet 12 to form a gap G between the positive electrode sheet 11 and the negative electrode sheet 12.

[0435] Embodiments

[0436] The following examples describe the present application in more detail, which are only used for illustrative purposes, because various modifications and changes within the scope of the present application are obvious to those skilled in the art. Unless otherwise stated, all parts, percentages and ratios reported in the following examples are based on mass, and all reagents used in the examples are commercially available or synthesized according to conventional methods and used directly without further purification, and the instruments used in the examples are commercially available.

[0437] Example 1

[0438] 1. Preparation of positive electrode sheet

[0439] The positive electrode sheet comprises a positive electrode current collector and a positive electrode film layer, the positive electrode film layer is located on both sides of the positive electrode current collector, the positive electrode current collector is an aluminum foil, and the positive electrode film layer is a film layer formed by uniformly coating a positive electrode slurry (the solvent is N-methyl pyrrolidone NMP) on the surface of the positive electrode current collector aluminum foil, and then drying and cold pressing, the positive electrode film layer comprises positive electrode active material, conductive agent carbon black (Super P) and binder polyvinylidene fluoride (PVDF) in a weight ratio of 97:1:2.

[0440] The positive electrode active material comprises a layered transition metal oxide with a molecular formula of LiNi 0.8 Co 0.1 Mn 0.1 O2(NCM811).

[0441] 2. Preparation of negative electrode sheet

[0442] The negative electrode sheet comprises a negative electrode current collector and a negative electrode film layer, the negative electrode film layer is located on both sides of the negative electrode current collector, the negative electrode current collector is a copper foil, and the negative electrode film layer is a film layer formed by uniformly coating a negative electrode slurry (the solvent is deionized water) on the surface of the negative electrode current collector copper foil, and then drying and cold pressing, the negative electrode film layer comprises silicon-based material (specifically silicon oxide compound), graphite, conductive agent carbon black, conductive agent carbon nanotube and binder polyacrylic acid in a weight ratio of 12.6:82.4:1.9:0.1:3.

[0443] The negative electrode film layer has an area density of 9.0 mg / cm 2 , a porosity of 22.1%, and a compacted density of 1.7 g / cm 3 .

[0444] 3. Separator

[0445] A PE (polyethylene) based film is provided.

[0446] Preparation of coating slurry: inorganic particles aluminum trioxide (Al2O3), first organic particles vinylidene fluoride-hexafluoropropylene copolymer (number average molecular weight 550,000), second organic particles styrene-vinyl acetate-pyrrolidone copolymer (number average molecular weight 80,000), dispersant sodium carboxymethyl cellulose (CMC-Na), wetting agent silicone modified polyether were mixed in a proper amount of solvent deionized water in a dry weight ratio of 70:20:8:1:1 to obtain a coating slurry with a solid content of 38% (by weight). Among them, the volume average particle size Dv50 of the inorganic particles aluminum trioxide (Al2O3) is 1 μm, the first organic particles are secondary particles with a number average particle size of 15 μm, and the second organic particles are primary particles with a number average particle size of 2 μm.

[0447] The coating slurry was coated on both surfaces of the PE base film, and through processes such as drying and slitting, an insulating piece was obtained.

[0448] 4. Preparation of electrolyte

[0449] The electrolyte includes an organic solvent and a lithium salt. Vinyl carbonate (EC), methyl ethyl carbonate (EMC), and diethyl carbonate (DEC) were mixed in a volume ratio of 1:1:1 to obtain an organic solvent, and then the fully dried lithium salt LiPF6 was dissolved in the mixed organic solvent to prepare an electrolyte with a lithium salt concentration of 1 mol / L.

[0450] 5. Preparation of cylindrical battery monomer

[0451] The above positive electrode sheet, insulating piece, and negative electrode sheet were stacked in order with the insulating piece between the positive electrode sheet and the negative electrode sheet to play a separating role. The positive electrode sheet, the insulating piece, and the negative electrode sheet were wound to obtain an electrode assembly. The electrode assembly was placed in a cylindrical structure shell, dried, and then injected with electrolyte. After vacuum packaging, standing, formation, shaping, and other processes, a cylindrical battery monomer was obtained. The electrode assembly is in a cylindrical structure, the shell is in a cylindrical structure, the shell includes a shell body and an end cover, the shell body includes an integrally formed side wall and an end wall, the side wall surrounds the electrode assembly, and the end cover and the end wall are opposite along the axial direction of the shell. The diameter of the cylindrical battery monomer is 46 mm, and the height is 95 mm.

[0452] Performance test

[0453] 1. Swelling volume test of battery monomer

[0454] The cylindrical battery monomer at 0% state of charge was immersed in silicone oil, and its mass was measured as m0.

[0455] The cylindrical battery monomer at 100% state of charge was immersed in silicone oil, and its mass was measured as m1.

[0456] The density of the silicone oil is p 硅油The volume change AV of the cylindrical battery cell between 100% state of charge and 0% state of charge is AV = (m0- m1) / p 硅油 The use reliability of the cylindrical battery cell is evaluated by AV. The smaller the AV, the smaller the volume expansion of the cylindrical battery cell, and the higher the use reliability. The larger the AV, the larger the volume expansion of the cylindrical battery cell, and the worse the use reliability.

[0457] The cylindrical battery cell is discharged at 0.33C to 2.5V at 25°C, and then discharged at 0.1C to 2.5V, at which time the cylindrical battery cell is at 0% state of charge. The cylindrical battery cell is charged at 0.33C to 4.25V at 25°C, and then charged at 0.1C to 4.25V, at which time the cylindrical battery cell is at 100% state of charge.

[0458] 2. Energy density test of the cylindrical battery cell

[0459] The first cycle discharge capacity (Ah) is multiplied by the ratio of the discharge voltage to the mass of the cylindrical battery cell at a constant voltage (4.25V in Example 1).

[0460] The energy density = first cycle discharge capacity (Ah) x discharge voltage (4.25V) / mass of the cylindrical battery cell (kg). The first cycle discharge capacity is tested according to the following steps: the cylindrical battery cell prepared above is fully charged at 1C and then fully discharged at 1C at 45°C, which is one cycle of charging and discharging, and the discharge capacity at this time is recorded, which is the first cycle discharge capacity.

[0461] 3. Cycle performance test of the battery

[0462] The cylindrical battery cell prepared above is fully charged at 1C and then fully discharged at 1C at 45°C, which is one cycle of charging and discharging, and the discharge capacity at this time is recorded, which is the first cycle discharge capacity. The cylindrical battery cell is tested for cycle charging and discharging according to the above method, and the discharge capacity after each cycle is recorded until the discharge capacity of the cylindrical battery cell decays to 80% of the initial discharge capacity, and the cycle number at this time is used to represent the cycle performance of the cylindrical battery cell. The higher the cycle number of the cylindrical battery cell, the better the cycle performance.

[0463] Examples 2-5

[0464] The battery cell is prepared by a method similar to Example 1, except that the preparation of the negative electrode sheet in Examples 2-5 includes the following steps:

[0465] The negative electrode sheet comprises a negative electrode current collector and a negative electrode film layer, the negative electrode film layer is located on both sides of the negative electrode current collector, the negative electrode current collector is a copper foil, the negative electrode film layer is a film layer formed by uniformly coating a negative electrode slurry (the solvent is deionized water) on the surface of the negative electrode current collector copper foil, and then drying and cold pressing, the negative electrode film layer comprises a silicon-based material (specifically a silicon oxide compound), graphite, a conductive agent carbon black, a conductive agent carbon nanotube, and a binder polyacrylic acid; and the mass content of the silicon element and the capacity surface density are adjusted.

[0466] Embodiments 6-9

[0467] The battery monomer is prepared by using a method similar to that of Embodiment 1, and different from Embodiment 1, the thickness of the side wall is adjusted in Embodiments 6-9.

[0468] The test results of each embodiment are shown in Table 1.

[0469] Table 1

[0470] Referring to Table 1, the energy density of the cylindrical battery monomer can be significantly improved by introducing silicon into the negative electrode active material. By providing organic particles on the separator, a gap can be formed between the positive electrode sheet and the negative electrode sheet, which can provide space for the expansion of the negative electrode sheet. Referring to Table 1, the expansion volume of the cylindrical battery monomer is less than or equal to 0.5 mL, the cycle number of the cylindrical battery monomer is greater than or equal to 800, and the cylindrical battery monomer has good reliability and cycle performance.

[0471] Referring to Embodiments 1-5, by adjusting the mass content of the silicon element, the capacity surface density can be adjusted synchronously, which is beneficial to improving the cycle performance and energy density of the battery monomer. The gap can provide space for the expansion of the negative electrode sheet, and when the content of the silicon element reaches 19%, the expansion volume of the cylindrical battery monomer is less than or equal to 0.5 mL, and the cycle number of the cylindrical battery monomer is greater than or equal to 800.

[0472] Referring to Embodiments 1 and 6-9, by adjusting the thickness of the side wall and cooperating with the mass content of the silicon element, it is beneficial to improving the cycle performance and energy density of the battery monomer, and the volume expansion of the battery monomer is small. The mechanical strength of the side wall made of steel is high, which can effectively improve the volume expansion problem, and can improve the cycle performance and energy density of the battery monomer.

[0473] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0474] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application, and are not intended to limit the same; although the present application has been described in detail with reference to the foregoing examples, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacements for some of the technical features, but these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A cylindrical battery cell having a diameter ≥ 40 mm, comprising: a housing; an electrode assembly at least partially housed within the housing; wherein the electrode assembly comprises a positive electrode sheet, a negative electrode sheet, and a separator, the positive electrode sheet, the negative electrode sheet, and the separator are wound together, the separator separates the positive electrode sheet and the negative electrode sheet, the negative electrode active material of the negative electrode sheet comprises at least one of a silicon-based material and a carbon-based material; at least one of the positive electrode sheet, the negative electrode sheet, and the separator comprises a base portion and a plurality of support portions, the base portion has two first surfaces oppositely arranged along a thickness direction of the base portion, the plurality of support portions protrude from at least one of the first surfaces to form a gap between the positive electrode sheet and the negative electrode sheet.

2. The cylindrical battery cell of claim 1, wherein, The support portions are configured to be compressible.

3. The cylindrical battery cell according to claim 1 or 2, wherein, The plurality of support portions comprises a first support portion and a second support portion, the first support portion protrudes from the first surface at a height greater than a height at which the second support portion protrudes from the first surface.

4. The cylindrical battery cell of claim 3, wherein, At least one of the positive electrode sheet, the negative electrode sheet, and the separator comprises a plurality of organic particles, the support portions comprise the organic particles.

5. The cylindrical battery cell of claim 4, wherein, The plurality of organic particles comprises a first organic particle and a second organic particle, the first organic particle has a number average particle size greater than a number average particle size of the second organic particle.

6. The cylindrical battery cell according to claim 4 or 5, wherein The plurality of support portions comprises a first support portion and a second support portion, the first support portion protrudes from the first surface at a height greater than a height at which the second support portion protrudes from the first surface; The plurality of organic particles comprises a first organic particle and a second organic particle; the first support portion comprises the first organic particle, and the second support portion comprises the second organic particle.

7. The cylindrical battery cell of any one of claims 4-6, wherein, The plurality of organic particles comprises a first organic particle, the first organic particle comprises one or more of a homopolymer or a copolymer of a fluorine-containing alkenyl monomer unit, a homopolymer or a copolymer of an olefin monomer unit, a homopolymer or a copolymer of an unsaturated nitrile monomer unit, a homopolymer or a copolymer of an alkylene oxide monomer unit, and a modified compound of each of the homopolymers or copolymers; Optionally, the first organic particle comprises one or more of polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, polyethylene, polypropylene, polyacrylonitrile, polyethylene oxide, a copolymer of different fluorine-containing alkenyl monomer units, a copolymer of a fluorine-containing alkenyl monomer unit and an olefin monomer unit, a copolymer of a fluorine-containing alkenyl monomer unit and an acrylic monomer unit, a copolymer of a fluorine-containing alkenyl monomer unit and an acrylate monomer unit, and a modified compound of each of the homopolymers or copolymers.

8. The cylindrical battery cell of any one of claims 4-7, wherein, The plurality of organic particles comprises a second organic particle, the second organic particle comprises one or more of a homopolymer or a copolymer of an acrylate monomer unit, a homopolymer or a copolymer of an acrylic monomer unit, a homopolymer or a copolymer of a styrene monomer unit, a polyurethane compound, a rubber compound, and a modified compound of each of the homopolymers or copolymers. Optionally, the second organic particles include one or more of a copolymer of an acrylic monomer unit and a styrene monomer unit, a copolymer of an acrylic monomer unit and a styrene monomer unit, a copolymer of an acrylic monomer unit-acrylate monomer unit-styrene monomer unit, a copolymer of a styrene monomer unit and an unsaturated nitrile monomer unit, a copolymer of a styrene monomer unit-olefin monomer unit-unsaturated nitrile monomer unit, and a modified compound of the above copolymers.

9. The cylindrical battery cell of any one of claims 1-8, wherein, The shell includes a side wall disposed around the electrode assembly, the side wall is made of steel, and the thickness of the side wall is 0.3-1.5 mm, optionally 0.3-1.2 mm.

10. The cylindrical battery cell of any one of claims 1-9, wherein, The negative electrode sheet includes a negative electrode current collector and a negative electrode film layer disposed on at least one side of the negative electrode current collector and containing the negative electrode active material, and the negative electrode active material includes a silicon-based material. The mass content of silicon in the silicon-based material in the negative electrode film layer is 2-19%, optionally 6-13%.

11. The cylindrical battery cell according to any one of claims 1 to 10, wherein, The capacity area density of the negative electrode sheet is greater than or equal to 3.2 mAh / cm 2 .

12. The cylindrical battery cell of claim 11, wherein, The capacity area density of the negative electrode sheet is 3.3 mAh / cm 2 to 11.5 mAh / cm 2 .

13. The cylindrical battery cell of claim 12, wherein, The capacity area density of the negative electrode sheet is 3.96 mAh / cm 2 to 7.56 mAh / cm 2 .

14. The cylindrical battery cell of any one of claims 1-13, wherein, The gap extends along the winding direction of the electrode assembly, and the gap has a winding start end and a winding end.

15. The cylindrical battery cell of claim 14, wherein, The radial dimension of at least part of the gap is 5-60 μm.

16. The cylindrical battery cell of claim 14 or 15, wherein, The radial dimension of the part of the gap near the winding start end is greater than or equal to the radial dimension of the part of the gap near the winding end.

17. The cylindrical battery cell of any one of claims 14-16, wherein, The radial dimension of at least part of the gap gradually decreases along the winding direction.

18. The cylindrical battery cell of any one of claims 14-17, wherein, The gap includes a middle region and two end regions arranged along the axial direction of the cylindrical battery cell, the middle region is located between the two end regions, and the radial dimension of the middle region is smaller than the radial dimension of the end regions.

19. The cylindrical battery cell of claim 18, wherein, The radial dimension of the gap gradually decreases in the direction from the end region to the middle region.

20. The cylindrical battery cell of any one of claims 1-19, wherein, The separator includes the base and a plurality of the support portions, and the support portions include organic particles disposed on the base.

21. The cylindrical battery cell of claim 20, wherein, The base of the separator includes a base film and an inorganic particle layer disposed on the base film, and the organic particles at least partially protrude from the inorganic particle layer.

22. The cylindrical battery cell according to any one of claims 1-21, wherein, The side of the positive electrode sheet facing the separator is provided with a plurality of the support portions, the side of the separator facing the positive electrode sheet is provided with a plurality of the support portions, and the plurality of the support portions of the positive electrode sheet facing the separator and the plurality of the support portions of the separator facing the positive electrode sheet are at least partially arranged opposite to each other; and / or, The side of the negative electrode sheet facing the separator is provided with a plurality of the support portions, the side of the separator facing the negative electrode sheet is provided with a plurality of the support portions, and the plurality of the support portions of the negative electrode sheet facing the separator and the plurality of the support portions of the separator facing the negative electrode sheet are at least partially arranged opposite to each other; and / or, The negative electrode sheet is provided with a plurality of support portions on the side facing the positive electrode sheet, and the positive electrode sheet is provided with a plurality of support portions on the side facing the negative electrode sheet. The plurality of support portions of the negative electrode sheet and the plurality of support portions of the positive electrode sheet are arranged opposite to at least part of each other.

23. The cylindrical battery cell of any one of claims 1-22, wherein, The spacer is provided with a plurality of support portions on both sides thereof. The gap includes a first gap and a second gap. The first gap is formed between the positive electrode sheet and the spacer, and the second gap is formed between the negative electrode sheet and the spacer.

24. The cylindrical battery cell of any one of claims 1-23, wherein, One of the positive electrode sheet and the negative electrode sheet includes a first tab, and the other includes a second tab. The cylindrical battery cell further includes an electrode terminal insulated from the end wall. One of the first tab and the second tab is electrically connected to the electrode terminal, and the other is electrically connected to the end wall. In the axial direction of the cylindrical battery cell, the first electrode lead-out portion and the second electrode lead-out portion are located on the same side of the electrode assembly.

25. The cylindrical battery cell of any one of claims 1-24, wherein, The housing includes a shell and an end cover. The shell includes an integrally formed side wall and an end wall. The side wall surrounds the electrode assembly. The end wall and the end cover are opposite to each other in the axial direction of the cylindrical battery cell. The end cover is sealingly connected to the side wall.

26. The cylindrical battery cell of claim 25, wherein, One of the positive electrode sheet and the negative electrode sheet includes a first tab, and the other includes a second tab. The cylindrical battery cell further includes an electrode terminal insulated from the end wall. One of the first tab and the second tab is electrically connected to the electrode terminal, and the other is electrically connected to the end wall.

27. The cylindrical battery cell of claim 26, further comprising a first current collecting member located on the side of the first tab facing the end wall and connected to the first tab. The electrode terminal abuts and is connected to the surface of the first current collecting member facing the end wall.

28. The cylindrical battery cell of claim 27, wherein, The electrode terminal is provided with a terminal recess on the side facing the first current collecting member, and / or the electrode terminal is provided with a terminal recess on the side facing away from the first current collecting member. The bottom wall of the terminal recess is welded to the first current collecting member.

29. The cylindrical battery cell of any one of claims 26-28, wherein, The first tab and the second tab are both located at the end of the electrode assembly facing the end wall.

30. The cylindrical battery cell of any one of claims 26-28, wherein, The first tab is located at the end of the electrode assembly facing the end wall, and the second tab is located at the end of the electrode assembly facing the end cover. The cylindrical battery cell further includes a second current collecting member connected to the second tab. The second current collecting member is connected to at least one of the end cover and the side wall.

31. The cylindrical battery cell of any one of claims 1-30, wherein, The height of the housing is 1.3 to 4 times the diameter of the housing.

32. The cylindrical battery cell of any one of claims 1-31, wherein, The height of the housing is 50 mm to 150 mm; and / or The diameter of the housing is 45 mm to 80 mm.

33. A battery comprising a plurality of cylindrical battery cells according to any one of claims 1-32.

34. An electrical device comprising the battery of claim 33, wherein the battery is configured to provide electrical energy.

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